Changed, Draw Lines and Draw Curve modes: "Auto-finish drawing" option now works regardless of "Continuous drawing" option (previously it worked only when the latter was enabled). 
Changed: position and size of the "Errors and Warnings" window is now stored while the editor is running.
Internal: rewritten parts of long texture names support code. It now involves much less special handling.
Updated ZDoom_DECORATE.cfg (A_QuakeEx, A_CheckBlock).
Updated ZDoom_ACS.cfg (QuakeEx).
Updated ZDoom ACC (QuakeEx).

Added "Sidedef Lower Texture", "Sidedef Middle Texture" and "Sidedef Upper Texture" Find and Replace modes.

Changed, Select Similar Sectors action: when "Effect" option is enabled, all sectors with at least one matching generalized/predefined effect will be selected.
Added, Tag Explorer plugin: a separate category for each generalized/predefined effect is now created when "Sort by action special" sort mode is used.
Added, Edit Effect window: normal and generalized effects can now be set at the same time.
Fixed, Edit Action window: in some cases Generalized actions were incorrectly processed.
Fixed, Edit Effect window: in some cases Generalized effects were incorrectly processed.
Fixed, Select Similar window: Tab control was incorrectly anchored.
Fixed, Nodes Viewer mode, cosmetic: segs angles were calculated incorrectly when showing nodes in classic format.
Fixed: HiRes textures, which didn't override any texture or flat were not loaded. 
Fixed, Tag Explorer plugin: linedef action categories were missing title when "Sort by action special" sort mode was used.
Cosmetic: renamed "Grid Setup" action to "Grid and Backdrop Setup".

Internal: removed some duplicate casts, marked some classes is IDisposable, some streams were disposed more than once.

A warning is now displayed when map uses more than one official IWAD as a resource.

Map saving: map lumps position in the wad is now kept persistent when saving it (previously / in DB2 map lumps were always pushed to the end of the wad when saving it). 
Internal: added NeutralResourcesLanguageAttribute to all assemblies. Theoretically this should result in a bit better performance when accessing embedded resources.
Updated ZDoom_DECORATE.cfg (A_Chase flags).

Game configurations: added 2 secret Sector_Set3dFloor flags. Shhh! Don't tell anybody!

Added, Draw Ellipse mode: angle setting can now be changed using "Rotate Clockwise" and "Rotate Counterclockwise" actions.
Added, Draw Line and Draw Curve modes: added "Auto-finish drawing" setting. When enabled, the modes will automatically finish drawing when currently drawn lines and already existing level geometry form a closed shape.
Changed: sector-wise linedef flipping is now done using the new "Align Linedefs" action. "Flip Linedefs" action works the same as in DB2 again.
Changed: when a map was already loaded, using "Open Map" action will use that map's directory as the starting directory.
Changed: official IWADs can no longer be saved.
Changed: disabled lump ranges/duplicate entries checks for official IWADs.
Changed: wad type is now preserved when saving a map (previously all wads were saved as PWADs).
Changed: moved Updater.exe launch much closer to the editor termination point to avoid any chance of it closing the editor before it properly closes itself.
Updated ZDoom_DECORATE.cfg (A_Blast).
Updated documentation.

Changed, cosmetic: elapsed time is now displayed after resources loading finishes.
Changed, internal: changed Clock.CurrentTime type to long.
Fixed, Tag Statistics window: in some cases the map view was not updated after selecting items in Sectors/Linedefs/Things columns. 
Fixed, cosmetic: Draw Curve mode icon was missing a shadow.

Fixed, Map Analysis mode: fixed a crash when running "Check Polyobjects" check on a map without lines using "Polyobj_StartLine" action.
Updated ZDoom_linedefs.cfg (Line_SetPortalTarget).
Updated ZDoom_ACS.cfg (Line_SetPortalTarget).

Changed, Game configurations: "Polyobject Anchor" things should not trigger "Thing outside the map geometry" error in the Map Analysis mode.
Updated ZDoom_DECORATE.cfg (A_SetScale).

Fixed, Visual mode: in some cases GLDEFS glow effect was not updated after changing floor/ceiling texture.
Fixed, Draw Rectangle and Draw Ellipse modes: in some cases pressing "Reset" button did not update the shape preview.
Fixed, DB2 bug: sector geometry was not updated after undoing "Flip Sidedefs" action.

Changed, Draw Ellipse mode: lowered minimum subdivisions to 3.
Fixed, Browse Action and Browse Effect windows: first option was always selected for any generalized action/effect parameter during generalized action/effect setup.

Changed, Draw Ellipse mode: Increase/Decrease bevel actions now always increase (and decrease) to the next even number.
Changed, Test Map drop-down: warning icon is now displayed when associated test engine executable can not be located, question icon is now displayed when the editor is unable to get the icon from the associated test engine executable.

Added, Draw Grid mode: "Lock slices to grid" now operates in 4 modes: "None", "Horizontal", "Vertical" and "Both". Can be helpful when drawing ladders and such.
Changed, all drawing modes: changeable drawing mode settings are now persistent.
Changed: "Dynamic grid size" mode is now disabled when changing grid size manually.
Documentation: "Command Line Parameters" topic contained a lot of incorrect information...
Updated ZDoom_DECORATE.cfg.

+A couple of cosmetic tweaks and fixes.
Updated ZDoom_DECORATE.cfg.

Fixed, Visual mode: fixed a crash, which happened after these steps: delete things in Classic mode -> undo things deletion in Visual mode -> redo things deletion in Visual mode.

Fixed, DB2 bug, Visual mode: in some cases (sidedef's sector ceiling lower than other side's sector floor) higher/lower sidedef picking was behaving incorrectly.

Added "Fixed Things Scale" setting (available in the View menu, as a button on the View toolbar and as the "Toggle Fixed Things Scale" action). When enabled, Things will no longer be scaled based on current zoom level in Classic modes, instead, thing bounding box will be drawn when appropriate (this option mimics DB1 things rendering style).
Internal: removed some remnants of fixed rendering pipeline from Renderer2D and Renderer3D.

Fixed, Visual mode: sector geometry was not updated after changing sector brightness under a 3D floor.

Added, "Find Thing Action and Arguments" search mode: "Any action" (-1) can now be used as a search input.
Fixed, "Find Linedef Action and Arguments" and "Find Sector Effect" search modes: in some cases action/effect was checked incorrectly when performing a search. 

Added, "Find Linedef Action and Arguments" search mode: "Any action" (-1) can now be used as a search input.
Added, "Find Sector Effect" search mode: "Any effect" (-1) can now be used as a search input.
Fixed, "Find Linedef Action and Arguments" search mode: generalized actions search was broken.
Fixed, General interface: in some cases the placeholder test engine was displayed in the "Test Map" drop-down.

Added, all drawing modes: added "Continuous drawing" option (available in the top mode menu / Draw Grid panel for the Draw Grid mode). When enabled, drawing mode will not be switched to previously active mode after finishing drawing a shape.
Fixed, general interlace: in some cases "Show Editable Vertices in Visual Mode" top toolbar button showed up when using Doom/Hexen map formats.
Fixed(?), Classic modes: probably fixed an rare issue when map element dragging was not starting when supposed to.

Fixed, Texture Browser window: in some cases navigating the textures list using up/down arrows caused an exception.
Fixed, Map Analysis window: fixed an exception on copying warnings to clipboard when the clipboard was used by other application.
Fixed, TEXTURES parser: added special handling for "TNT1A0" sprite name so a texture with this sprite as a single patch is no longer treated as failed loading.
Fixed, Visual mode: in some cases (like line slopes used in several adjacent sectors) sector effect updates were triggered multiple times for the same sector, resulting in noticeable slowdowns and in some cases in infinite recursion.
Updated ZDoom ACC.

Fixed, Things mode: Undo for things cloning by Shift-dragging them was created incorrectly (cloned things were moved to their initial position, but not removed).
Fixed, Visual mode: fixed Classic sky texture generation artifact when Bilinear filtering was enabled in Visual mode.
Fixed, Visual mode: fixed Classic sky texture generation artifact when non-power-of-2 Sky textures were used.
Fixed, Visual mode: dynamic lights flickering on surfaces nearly-perpendicular to lights centers should be much harder to trigger now.

Fixed, Visual mode: some video memory was not released after closing a map if the Visual mode was enabled at least once during the editing session, eventually resulting in E_OUTOFMEMORY crash.
Fixed, General interface, cosmetic: in some cases the warnings label was disabled in a flashing state (e.g. with red background).
Internal: moved some older GZDB actions form GZGeneral to MapManager. They can no longer be toggled when no map is loaded (which is probably for the best).
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.

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, 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.

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.

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.

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