Added, Visual mode: "Raise/Lower Floor/Ceiling to adjacent Sector" actions now take surrounding 3d floors into account.
Added, Visual mode: highlight/selection based on texture alpha now works on 3d floors.
Changed, Game configurations, TranslucentLine:208 action: renamed the second argument from "Translucency Amount" to "Opacity".
Internal, documentation: updated udmf_zdoom.txt.

Fixed, DB2 bug: hlsl effect stream was not rewound when trying to compile it in debug mode, which resulted in always receiving IndexOutOfRangeException when trying to do it.
Fixed, Visual mode: textures on floors, ceilings and single-sided wall parts are now rendered ignoring texture alpha.
Changed, Game configurations, Sector_Set3dFloor:160 action: renamed the fourth argument from "Alpha" to "Opacity".

Fixed, Visual mode: in some cases ceiling glow effect was interfering with Transfer Brightness effect resulting in incorrectly lit sidedef geometry.
Fixed, Visual mode: UDMF sidedef brightness should be ignored when a wall section is affected by Transfer Brightness effect.
Fixed, Visual mode: any custom fog should be rendered regardless of sector brightness. 
Fixed, Visual mode: "fogdensity" and "outsidefogdensity" MAPINFO values were processed incorrectly.
Fixed, Visual mode: in some cases Things were rendered twice during a render pass.
Fixed, Visual mode: floor glow effect should affect thing brightness only when applied to floor of the sector thing is in.
Fixed, TEXTURES parser: TEXTURES group was named incorrectly in the Textures Browser window when parsed from a WAD file.
Fixed, MAPINFO, GLDEFS, DECORATE parsers: "//$GZDB_SKIP" special comment was processed incorrectly.
Fixed, MAPINFO parser: "fogdensity" and "outsidefogdensity" properties are now initialized using GZDoom default value (255) instead of 0.

Updated ZDoom ACC.
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.

Fixed a crash when trying to parse an empty TEXTURES lump (probably covers some other empty text lumps as well).
Added strict revision checking to BuilderModes.dll (this plugin must always stay in sync with the core).

Fixed, Map conversion: game mode flags were ignored when converting from Doom map format to UDMF.
Fixed, Edit Selection mode: when "Drag selection automatically on paste" setting was enabled, it was possible to start rotating/scaling map elements instead of dragging them after pasting.

Changed, "Open map in current wad" action: current map resources are now carried over to the map being switched to.

Fixed, Visual mode: fixed a crash when creating classic skybox texture when sky texture's height was less than 28 pixels.

DECORATE support: added a warning when a sprite assigned using "$sprite" special comment does not exist. 

Fixed, Edit Thing window: fixed a crash when entering thing type in the Type field when a filter was applied to the things list.
Fixed, MAPINFO parser: in some cases the parser was skipping the whole file instead of current map block while parsing classic map definition.
Fixed, Visual mode: classic sky model had incorrect rotation.

Fixed, Visual mode: fixed inability to drag auto-selected sidedef parts using mouse when "Synchronize selection between Visual and Classic modes" setting was enabled.
Fixed, Visual mode: fixed incorrect auto-selected sidedefs texture offset clamping when "Synchronize selection between Visual and Classic modes" setting was enabled.

Fixed a crash during skybox textures search when searching for any image and not finding it in the first PK3 or Directory resource.
Fixed: TGA image detection required a special approach...
Fixed, Visual mode: built-in sky texture should not be mirrored like the classic ones.

Updated skybox model to better match GZDoom's skybox. Also the sky texture was flipped horizontally.
Fixed, Visual mode: "Select with the same texture" action is now able to select sidedef parts only visible because of slopes.
Fixed, Visual mode: skybox texture was not updated after using "Open map in current wad" action.
Fixed, Visual mode: in some cases Visual camera was placed below sector's floor when "Sync camera position between 2D and 3D modes" setting was enabled.
Fixed: numeric thing flags with inverted UDMF flag defined in "thingflagstranslation" Game configuration block were lost when copy-pasting a thing.
Fixed, command line arguments: fixed a crash when loading a map from a wad with existing .dbs file.

Fixed, Visual mode: fixed D3DERR_INVALIDCALL error caused by a bug in classic skybox texture creation.
Fixed, Visual mode: aspect ratio was not updated when render area was resized.
Fixed, Visual mode: vertex handles were disappearing after using Reload Resources (F8) action.
Changed, internal: removed most of the fixed pipeline rendering code. The editor can no longer be used on a video card without Shader Model 2.0 support. 

Fixed, Visual mode: "Select with the same texture" action should not select invisible geometry (like sidedef parts hidden by slopes).
Changed, Sector drawing: default sector height is now used when the nearest sector's height is <= 0.

Fixed a crash when trying to get map title after closing Map options window.
Updated game configurations (Sector_SetPortal).

Fixed, Visual mode: "render as sky" flag was not updated for upper wall geometry when pasting textures (and in some other cases).

Added "Toggle sky rendering" action and toolbar button.
Added, MAPINFO parser: the editor now recognizes map number from classic map definition format. Hexen MAPINFO is now properly parsed.
Added, MAPINFO support: if current map definition contains map name as a text string, it will be shown in the editor's header.
Changed: "Toggle dynamic lights rendering" now toggles between "Don't show dynamic lights" and "Show dynamic lights" when used in Classic modes. 
Changed, Things mode: lowered the opacity of dynamic light radii.
Changed, (G)ZDoom text parsers: empty include files now trigger a warning instead of an error and no longer abort parsing.
Fixed, Game configurations: moved Stalagmite:5050 thing to Doom block (so the editor no longer tries to load it for non-Doom game configurations).
Fixed(?), Visual mode: probably fixed a hard-to-trigger exception when sorting translucent geometry.
Fixed, Visual mode: floor glow effect was incorrectly applied to walls (was broken in R2452).
Internal: restructured most of MAPINFO and GLDEFS parsers. Should be more maintainable now.  
Updated ZDoom ACC.
Updated zdbsp to 1.19.
Updated documentation.

Updated ZDoom_DECORATE.cfg.

MODELDEF, DECORATE, GLDEFS parsers: fixed a crash when checking a file path when said path contained unsupported characters.

Externalized most of the editor's built-in textures. You can find (and replace) them in the "[GZDB]\Textures" folder.

Fixed a typo.

Fixed a crash after pressing "Edit Selection" button in the Find and Replace window when several instances of the same map element were selected.
Redesigned the Test Map button's drop-down: test engines are now shown and behave the same way as skills and also have appropriate icons. 

Fixed, Thing/Linedef edit forms: fixed a crash during form setup when Action was either unknown or generalized.
Fixed, ANIMDEFS parser: in some cases the parser was unable to read camera texture name.

Fixed, Map Analysis mode, "Check stuck things" check: rewritten parts of the flags checking logic to allow more accurate flag checks.
Fixed, Map Analysis mode: fixed a crash when trying to dissolve an invalid sector when one of it's linedefs referenced it on the both sides.
Fixed, Sectors mode: fixed incorrect undo description when deleting sectors.
Internal: joined declaration and assignment of some more variables.

Internal: joined declaration and assignment of some variables.

Fixed, GLDEFS parser: in some cases the parser was unable to detect the end of "Glow" block, which resulted in skipping the rest of the file.

Updated ZDoom ACC and ZDoom_ACS.cfg (added GetInventoryMax()).

Fixed, ACS parser: absolute and relative include paths handling was broken in R2448.

Fixed, ANIMDEFS parser: camera texture names are limited to 8 chars in ZDoom.
Fixed, Game configurations: Stalagtite:47 thing was named Stalagmite.
Changed, Game configurations: moved Stalagmite:5050 thing to the "Obstacles" category.

Some internal changes in text parsers logic.

Fixed, Script Editor: in some cases clicking on an error in the errors list didn't navigate to the error location.
Fixed, Script Editor: in some cases incorrect error line number was shown.
Fixed, Text lump parsers: fixed a crash when trying to get a filename from a quoted string with missing closing quote.
Fixed, Text lump parsers: in several cases parsing errors were ignored by overlaying data structures.
Fixed: in some cases Thing Filter thing flags were cleared when switching game configurations in the "Game Configurations" window.
Changed, PK3 reader: loading of files with invalid path chars is now skipped instead of skipping loading of the whole resource. Also more helpful warning message is now displayed.
Updated SharpCompress library to v.0.11.2.0.

Added, Things mode: dynamic light things light radii are now rendered (can be disabled by setting "Dynamic light mode" to "Don't show dynamic lights" on the top toolbar).
Internal, Renderer2D.RenderArrows(): only visible lines are now rendered.
Internal, API: renamed public Line3D properties: v1 to Start, v2 to End, color to Color, renderarrowhead to RenderArrowhead.

Changed, Renderer2D: StartOverlay() now works the same way as StartPlotter() and StartThings() (e.g. returns false when unable to render instead of throwing an Exception. Should prevent crashes for people with slow GPUs / very complex maps).