"Preferences -> Editing -> When splitting a linedef" setting is now always used when splitting linedefs.
"Preferences -> Editing -> When splitting a linedef": added "Reset X and Y" option.
"Preferences -> Editing -> Auto-align textures of newly created linedefs" option now works in a more intelligent fashion.
Draw Curve Mode: added settings panel.
Sectors mode: added "Make Door" button to the toolbar.
Swapped Side panel and Info panel z-order.
Interface: split toolbar into 3 separate toolbars. All toolbar buttons are now viewable at 1024x768.
Interface: grouped stuff in "Modes" menu a bit better.
Interface: added "Draw [stuff]" buttons to modes toolbar.
Interface: reorganized main menu. Hope it makes more sense now.
API: added General.Interface.AddModesButton() and General.Interface.AddModesMenu(), which can be used to add buttons to specific group in "Modes" toolbar and menu items to specific group in "Modes" menu, so actions, which behave like an editing mode, but are not part of one can be added there.