Alt key gets stuck intermittently when 'Show position of pointer when the Control key is pressed' setting is active in the OS #52905

New Issue

Davy Herben · 2017-09-26T11:45:17+02:00

Davy Herben commented

2017-09-26 11:45:17 +02:00

System Information
LinuxMint 18.2 (Cinnamon), GTX980M on Alienware 17R3

Blender Version
Broken: 2.79-1505206035a-0thomas~xenial0 (Thomas Schiekx PPA)

I believe this is a variation of the recurring 'modifier keys don't like deactivating and reactivating windows' theme. Logging this mostly to help others with the same issue.

The symptoms:

When working in blender, the Alt key frequently gets stuck. This happens in combination with the CTRL key, e.g. when I press CTRL+S, CTRL+ALT+S gets registered, and blender shows the Save As screen. It happens in all views (e.g. in the Save As view, I can not select a filename). Tapping the Alt key gets it unstuck, but it gets stuck again after pressing the Ctrl key. The stickiness does not happen on every CTRL press, I would say about 50% of the time. It makes blender completely unworkable.

I have installed the Screencast Keys addon, and it includes the fake ALT key presses (i.e. it shows CTRL+ALT+S). I have also installed key-mon, a similar tool on the OS level, and that does NOT include said ALT key presses (i.e. it shows CTRL+S). I have tried several keyboards, always same results.

I have traced the issue to the 'Show position of pointer when the Control key is pressed' toggle in Cinnamons Mouse and Touchpad settings. The function of this toggle is to display a short animation around the mouse cursor to locate it on the screen, whenever the CTRL key is pressed by itself. MacOS has a similar feature.

I have run blender with --debug-events, with the following results:

Show position of pointer ON, no fake ALT registered:

wm_event_do_handlers: Handling event
wmEvent  type:260 / WINDOW_DEACTIVATE, val:1 / PRESS,
         shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0,
         mouse:(845,1027), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8a70f88

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:1 / PRESS,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31208

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:1 / PRESS,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288
wm_handlers_do_intern:       handled! 'WM_OT_save_mainfile'

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:2 / RELEASE,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:2 / RELEASE,
         shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

Show position of pointer ON, fake ALT registered:


wm_event_do_handlers: Handling event
wmEvent  type:260 / WINDOW_DEACTIVATE, val:2 / RELEASE,
         shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0,
         mouse:(519,518), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31208

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:1 / PRESS,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31308

wm_event_do_handlers: Handling event
wmEvent  type:214 / RIGHT_ALT, val:1 / PRESS,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:1 / PRESS,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31388
wm_handlers_do_intern:       handled! 'WM_OT_save_as_mainfile'

wm_event_do_handlers: Handling event
wmEvent  type:20512 / UNKNOWN, val:1 / PRESS,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:115,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288
ED_screen_refresh: set screen
wm_handlers_do_intern:       handled! 'FILE_OT_highlight'

wm_event_do_handlers: Handling event
wmEvent  type:272 / TIMER, val:0 / NOTHING,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31388

wm_event_do_handlers: Handling event
wmEvent  type:272 / TIMER, val:0 / NOTHING,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:2 / RELEASE,
         shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:2 / RELEASE,
         shift:0, ctrl:0, alt:3, oskey:0, keymodifier:0,
         mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

Show position of pointer OFF, no fake ALT registered:

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:1 / PRESS,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:1 / PRESS,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288
wm_handlers_do_intern:       handled! 'WM_OT_save_mainfile'

wm_event_do_handlers: Handling event
wmEvent  type:115 / S, val:2 / RELEASE,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:272 / TIMER, val:0 / NOTHING,
         shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

wm_event_do_handlers: Handling event
wmEvent  type:212 / LEFT_CTRL, val:2 / RELEASE,
         shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0,
         mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288

As you can see, having the option on causes a WINDOW_DEACTIVATE event whenever the CTRL key gets pressed. In the case where it goes wrong, blender registers a RIGHT_ALT pressed event, without a corresponding release event.

I hope this helps to solve the problem. I have worked around it by simply switching off the option.

**System Information** LinuxMint 18.2 (Cinnamon), GTX980M on Alienware 17R3 **Blender Version** Broken: 2.79-1505206035a-0thomas~xenial0 (Thomas Schiekx PPA) I believe this is a variation of the recurring 'modifier keys don't like deactivating and reactivating windows' theme. Logging this mostly to help others with the same issue. The symptoms: When working in blender, the Alt key frequently gets stuck. This happens in combination with the CTRL key, e.g. when I press CTRL+S, CTRL+ALT+S gets registered, and blender shows the Save As screen. It happens in all views (e.g. in the Save As view, I can not select a filename). Tapping the Alt key gets it unstuck, but it gets stuck again after pressing the Ctrl key. The stickiness does not happen on every CTRL press, I would say about 50% of the time. It makes blender completely unworkable. I have installed the Screencast Keys addon, and it includes the fake ALT key presses (i.e. it shows CTRL+ALT+S). I have also installed key-mon, a similar tool on the OS level, and that does NOT include said ALT key presses (i.e. it shows CTRL+S). I have tried several keyboards, always same results. I have traced the issue to the 'Show position of pointer when the Control key is pressed' toggle in Cinnamons Mouse and Touchpad settings. The function of this toggle is to display a short animation around the mouse cursor to locate it on the screen, whenever the CTRL key is pressed by itself. MacOS has a similar feature. I have run blender with --debug-events, with the following results: * Show position of pointer ON, no fake ALT registered: ``` wm_event_do_handlers: Handling event wmEvent type:260 / WINDOW_DEACTIVATE, val:1 / PRESS, shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0, mouse:(845,1027), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8a70f88 wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:1 / PRESS, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31208 wm_event_do_handlers: Handling event wmEvent type:115 / S, val:1 / PRESS, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_handlers_do_intern: handled! 'WM_OT_save_mainfile' wm_event_do_handlers: Handling event wmEvent type:115 / S, val:2 / RELEASE, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(845,1029), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:2 / RELEASE, shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 ``` * Show position of pointer ON, fake ALT registered: ``` wm_event_do_handlers: Handling event wmEvent type:260 / WINDOW_DEACTIVATE, val:2 / RELEASE, shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0, mouse:(519,518), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31208 wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:1 / PRESS, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31308 wm_event_do_handlers: Handling event wmEvent type:214 / RIGHT_ALT, val:1 / PRESS, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:115 / S, val:1 / PRESS, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31388 wm_handlers_do_intern: handled! 'WM_OT_save_as_mainfile' wm_event_do_handlers: Handling event wmEvent type:20512 / UNKNOWN, val:1 / PRESS, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:115, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 ED_screen_refresh: set screen wm_handlers_do_intern: handled! 'FILE_OT_highlight' wm_event_do_handlers: Handling event wmEvent type:272 / TIMER, val:0 / NOTHING, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31388 wm_event_do_handlers: Handling event wmEvent type:272 / TIMER, val:0 / NOTHING, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:115 / S, val:2 / RELEASE, shift:0, ctrl:1, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:2 / RELEASE, shift:0, ctrl:0, alt:3, oskey:0, keymodifier:0, mouse:(519,519), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 ``` * Show position of pointer OFF, no fake ALT registered: ``` wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:1 / PRESS, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:115 / S, val:1 / PRESS, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_handlers_do_intern: handled! 'WM_OT_save_mainfile' wm_event_do_handlers: Handling event wmEvent type:115 / S, val:2 / RELEASE, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:272 / TIMER, val:0 / NOTHING, shift:0, ctrl:1, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 wm_event_do_handlers: Handling event wmEvent type:212 / LEFT_CTRL, val:2 / RELEASE, shift:0, ctrl:0, alt:0, oskey:0, keymodifier:0, mouse:(899,904), ascii:'', utf8:'', keymap_idname:(null), pointer:0x7fadb8b31288 ``` As you can see, having the option on causes a WINDOW_DEACTIVATE event whenever the CTRL key gets pressed. In the case where it goes wrong, blender registers a RIGHT_ALT pressed event, without a corresponding release event. I hope this helps to solve the problem. I have worked around it by simply switching off the option.

Davy Herben commented

2017-09-26 11:45:17 +02:00

Changed status to: 'Open'

Davy Herben commented

2017-09-26 11:45:17 +02:00

Added subscriber: @dherben

Ray molenkamp commented

2017-09-28 19:15:17 +02:00

Added subscribers: @Sergey, @LazyDodo

Sergey Sharybin was assigned by Ray molenkamp

2017-09-28 19:15:17 +02:00

Ray molenkamp commented

2017-09-28 19:15:17 +02:00

Seems like a linux/ghost thing, mind taking a peek here @Sergey?

Sergey Sharybin commented

2017-10-02 09:45:00 +02:00

GHOST simply converts X11 events to more Blender understandable ones, there is no place in code which will trigger right alt event wuthout corresponding X11 event.

Does the same happen when you press control in xev ?

GHOST simply converts X11 events to more Blender understandable ones, there is no place in code which will trigger right alt event wuthout corresponding X11 event. Does the same happen when you press control in `xev` ?

Bastien Montagne commented

2017-10-10 10:49:06 +02:00

Added subscriber: @mont29

Bastien Montagne commented

2017-10-10 10:49:06 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2017-10-10 10:49:06 +02:00

Bastien Montagne commented

2017-10-10 10:49:06 +02:00

There is a rampant issue with alt key and Blender since years, under Linux (Gnome at least)… When you use alt-tab combo to switch between apps, Blender detects alt-down before losing focus, but sometimes it gets focus back too late somehow, and does not get the 'alt-up' event, so it still believes alt is pressed until you press/release it again. Point being, keyboard handling by modern desktops is rather complex and not always fully consistent.

Anyway, more than a week without reply. Due to the policy of the tracker archiving for until required info/data are provided.

There is a rampant issue with alt key and Blender since years, under Linux (Gnome at least)… When you use alt-tab combo to switch between apps, Blender detects alt-down before losing focus, but sometimes it gets focus back too late somehow, and does not get the 'alt-up' event, so it still believes alt is pressed until you press/release it again. Point being, keyboard handling by modern desktops is rather complex and not always fully consistent. Anyway, more than a week without reply. Due to the policy of the tracker archiving for until required info/data are provided.

kursad k commented

2023-02-27 06:45:09 +01:00

There is a rampant issue with alt key and Blender since years, under Linux (Gnome at least)… When you use alt-tab combo to switch between apps, Blender detects alt-down before losing focus, but sometimes it gets focus back too late somehow, and does not get the 'alt-up' event, so it still believes alt is pressed until you press/release it again. Point being, keyboard handling by modern desktops is rather complex and not always fully consistent.

Anyway, more than a week without reply. Due to the policy of the tracker archiving for until required info/data are provided.

I have this exact issue on Windows 11. Blender has the alt key as stuck or pressed when Coming from other apps via alt-tab. Bear in mind that Blender seems to be the only app that is acting this way, no app has the alt key anomaly when changing between apps.

> There is a rampant issue with alt key and Blender since years, under Linux (Gnome at least)… When you use alt-tab combo to switch between apps, Blender detects alt-down before losing focus, but sometimes it gets focus back too late somehow, and does not get the 'alt-up' event, so it still believes alt is pressed until you press/release it again. Point being, keyboard handling by modern desktops is rather complex and not always fully consistent. > > Anyway, more than a week without reply. Due to the policy of the tracker archiving for until required info/data are provided. > I have this exact issue on Windows 11. Blender has the alt key as stuck or pressed when Coming from other apps via alt-tab. Bear in mind that Blender seems to be the only app that is acting this way, no app has the alt key anomaly when changing between apps.

Sergey Sharybin commented

2023-02-27 11:24:55 +01:00

It might be better idea to submit a new report. This one is different platform and is quite old.
If the issue is still there and covers multiple platforms we can/should start new investigation.

It might be better idea to submit a new report. This one is different platform and is quite old. If the issue is still there and covers multiple platforms we can/should start new investigation.

👍 1

kursad k commented

2023-02-28 03:56:21 +01:00

If anyone ends up in this issue please follow up on the new one that I opened

#105277

If anyone ends up in this issue please follow up on the new one that I opened https://projects.blender.org/blender/blender/issues/105277

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Alt key gets stuck intermittently when 'Show position of pointer when the Control key is pressed' setting is active in the OS #52905