The editor will fail more gracefully when no D3D device is detected.
In some cases the editor was constantly checking D3D device availability when minimized.
Added more DX-related debug output (only in Debug builds).
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.
Configurations: all 64 game configuration are now available by default.
Game Configurations window: game configurations can now be disabled. This setting is mostly cosmetic. When a game configuration is disabled, it won't be shown in "game configuration" dropdowns in New\Open Map Options and Map Options windows. If a map's .dbs file specifies a disabled configuration, it will be picked as a map configuration anyway.
Linedefs mode: vertex insert preview logic used Highlight range instead of Stitch range (which is used when draw mode engages).
Visual mode: double-sided middle textures were not selected when using "Select" action with "with same texture" modifier.
Textures: some optimizations in patch blending code.
ZDoom ACS script configuration: added definitions for StrLeft, StrMid and StrRight functions.
Numeric textbox: in addition to '++NN' and '--NN', you can use '*NN' and '/NN' to multiply or divide the values.
Configurations, ZDoom_linedefs.cfg: some linedef action arguments were missing a proper type.
Rewritten parts of hints system. Hints are now loaded from "Hints.cfg" file.
When Draw Rectangle or Draw Ellipse mode is enabled, it's settings are now shown in side panel.
Draw Ellipse mode: increased maximum number of sides to 512.
Changed the way tags are shown in Tag Selector controls. Tags without labels are now shown as a number (not "Tag N"), and tags with label are now shown as "N (label)", not "label (N)".
Tag labels are now shown in Thing, Sector and Linedef info panels.
Once again changed the way things are rendered while dragged.
Rearranged the label in PairedIntControl and PairedFieldControl (it is now behind numeric controls).
Optimized MapSet.GetSectorByCoordinates().
Sectors mode: optimized sector highlight rendering logic.
Sectors mode: optimized sector effect/tag labels update logic.
Geometry tools: optimized several core functions.
Hints for current editing mode can now be displayed when nothing is highlighted (currently the hints are shown only in Draw Geometry mode).
GZDB is now build with LARGEADDRESSAWARE flag, which increases amount of RAM GZDB can use from 1.4 to 2.8 GB.
Texture scale controls now have "Link" button.
Thing, Sector (UDMF) and Linedef edit forms now work in realtime mode.
Some more fixes in Edit form realtime update stuff.
Removed some unused variables and functions.
Added two new type handlers that can be used in UDMF ('Thing Type' and 'Thing Class')
Polished the browse icons and browse buttons.
Added more events for plugins to intercept.