UI: Support using Ctrl+Scrollwheel to cycle properties editor tabs

Small side effect is that area operators (toggle fullscreen/maximized, duplicate
area) are now displayed in RMB-menu. Makes sense anyway.

source/blender/editors/include/ED_screen.h

@@ -364,4 +364,10 @@ void ED_area_type_hud_ensure(struct bContext *C, struct ScrArea *sa);
 #define ED_KEYMAP_GPENCIL   32
 #define ED_KEYMAP_HEADER    64
 
+/* SCREEN_OT_space_context_cycle direction */
+enum {
+	SPACE_CONTEXT_CYCLE_PREV,
+	SPACE_CONTEXT_CYCLE_NEXT,
+};
+
 #endif /* __ED_SCREEN_H__ */

source/blender/editors/screen/screen_ops.c

@@ -4614,12 +4614,6 @@ static void SCREEN_OT_region_blend(wmOperatorType *ot)
 /** \name Space Context Cycle Operator
  * \{ */
 
-/* SCREEN_OT_space_context_cycle direction */
-enum {
-	SPACE_CONTEXT_CYCLE_PREV,
-	SPACE_CONTEXT_CYCLE_NEXT,
-};
-
 static const EnumPropertyItem space_context_cycle_direction[] = {
 	{SPACE_CONTEXT_CYCLE_PREV, "PREV", 0, "Previous", ""},
 	{SPACE_CONTEXT_CYCLE_NEXT, "NEXT", 0, "Next", ""},

source/blender/editors/space_buttons/space_buttons.c

@@ -351,8 +351,14 @@ static void buttons_operatortypes(void)
 static void buttons_keymap(struct wmKeyConfig *keyconf)
 {
 	wmKeyMap *keymap = WM_keymap_ensure(keyconf, "Property Editor", SPACE_BUTS, 0);
+	wmKeyMapItem *kmi;
 
 	WM_keymap_add_item(keymap, "BUTTONS_OT_context_menu", RIGHTMOUSE, KM_PRESS, 0, 0);
+
+	kmi = WM_keymap_add_item(keymap, "SCREEN_OT_space_context_cycle", WHEELUPMOUSE, KM_PRESS, KM_CTRL, 0);
+	RNA_enum_set(kmi->ptr, "direction", SPACE_CONTEXT_CYCLE_PREV);
+	kmi = WM_keymap_add_item(keymap, "SCREEN_OT_space_context_cycle", WHEELDOWNMOUSE, KM_PRESS, KM_CTRL, 0);
+	RNA_enum_set(kmi->ptr, "direction", SPACE_CONTEXT_CYCLE_NEXT);
 }
 
 /* add handlers, stuff you only do once or on area/region changes */
@@ -410,7 +416,11 @@ static void buttons_header_region_message_subscribe(
 
 static void buttons_navigation_bar_region_init(wmWindowManager *wm, ARegion *ar)
 {
+	wmKeyMap *keymap = WM_keymap_ensure(wm->defaultconf, "Property Editor", SPACE_BUTS, 0);
+	WM_event_add_keymap_handler(&ar->handlers, keymap);
+
 	ar->flag |= RGN_FLAG_PREFSIZE_OR_HIDDEN;
+
 	ED_region_panels_init(wm, ar);
 	ar->v2d.keepzoom |= V2D_LOCKZOOM_X | V2D_LOCKZOOM_Y;
 }