BF-admins agree to remove header information that isn't useful,
to reduce noise.
- BEGIN/END license blocks
Developers should add non license comments as separate comment blocks.
No need for separator text.
- Contributors
This is often invalid, outdated or misleading
especially when splitting files.
It's more useful to git-blame to find out who has developed the code.
See P901 for script to perform these edits.
Was using UI_BLOCK_LOOP to control draw style,
this meant we couldn't use popup theme colors for cases
where it the interface has the same purpose as a popup but happens
not to use this flag.
block and layout could be NULL and checking this everywhere
wasn't practical.
Instead of lazy initializing, add UI_popup_menu_end_or_cancel
which cancels empty popup menus.
