Added "Apply Directional Shading" mode. It can be used to apply directional colored flat shading to sloped terrain sectors (line and vertex slopes are supported) and sidedefs.
Updated ZDoom ACC.
Updated ZDoom_ACS.cfg.

Fixed: copied sidedef settings were not applied when using "Paste properties" and "Paste properties special" actions in Doom/Hexen map formats.

Removed, GLDEFS parser: removed GLOOME glow definitions support code.

Updated, Curve Linedefs mode: distance/angle are now changed using bigger increments when being modified by mouse-dragging. You can hold Shift to enable increments by 1 unit.
Updated, Curve Linedefs mode: changing angle by mouse-dragging when "Fixed circular curve" option is enabled is now performed in a more predictable way.
Updated, Curve Linedefs mode: generated geometry is now merged with existing geometry.
Added, Curve Linedefs mode: a hint label is now displayed when modifying settings using mouse-dragging.
Added, Curve Linedefs mode: number of curve vertices can now be changed using LMB+RMB-drag.

Optimized map geometry merging performance when pasting map geometry.
Added, Curve Linedefs mode: added "Flip Curve" button.
Updater: partially rewrote fix from the previous commit.

Changed, Curve Linedefs mode: re-designed the mode UI. Alternative control options are now available (check Help tab while the mode is active).
Changed, Curve Linedefs mode: changed curve generation logic. Setting Distance to 0 will now divide selected linedefs into equal parts.
Changed, Curve Linedefs mode: curve vertices are now drawn.
Updated ZDoom_DECORATE.cfg.

Added, Game configurations: added "ignoreddirectories" parameter. It lists directory names to be ignored when loading PK3/PK7/Directory resources.
Added, Game configurations: added "ignoredextensions" parameter. It lists file extensions to be ignored when loading PK3/PK7/Directory resources.
Updated: sector triangulation logic now works ~20% faster.
Changed: a case when a pk3/pk7 archive contains several entries with identical filename is now treated as a warning, not as an error.
Fixed, Visual mode: absolute floor/ceiling brightness should not be affected by brightness transfer effects (like 3d floors).
Fixed, Draw Lines mode: in some cases unclosed sectors were created when several points were successively drawn at the same location.
Updated documentation. 

Updated ZDoom_DECORATE.cfg.
Updated documentation ("Game Configuration - Sectors Settings" page).

Added, Things mode: sound radii are now shown for "Custom Ambient Sound" and "Custom Ambient Sound (no gravity)" things.

Fixed, Visual mode: things in sectors affected by line slope effect were not updated when sector height was indirectly changed.
Game configurations: added "internalsoundnames" property.
Updated documentation ("Game Configuration - Basic Settings" page).

Added, Things mode: minimum/maximum sound radii can now be displayed for ZDoom's Ambient Sound things.
Added, Things mode: added "Show Light Radii" and "Show Sound Radii" main toolbar and View menu buttons.
Fixed, Action arguments control: invisible splitter between args1-3 and args4-5 is no longer draggable.
Updated ZDoom ACC (SetTranslation).
Updated ZDoom_ACS.cfg (SetTranslation).

Changed, Vertices/Linedefs/Sectors/Things modes: selected map element is no longer deselected after accepting Edit window when it was the only selected map element when the Edit window was opening.

Added: guidelines can now be enabled in Draw Rectangle/Ellipse/Grid modes.
Changed, Draw Lines mode: perpendicular guidelines are now drawn for horizontal/vertical lines.
Updated, Draw Ellipse mode: the shape now always touches all sides of the bounding box.
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.
Updated ZDoom ACC.

Changed, Visplane Explorer mode: calculated data is now fully reset when toggling "Open doors" option.
Changed, Visplane Explorer mode: vpo.dll is now initialized when entering the mode instead of after opening a map.
Fixed inconsistent Hexen Puzzle Gears names between game configuration and spawn numbers list.
Updated ZDoom_DECORATE.cfg (GetMissileDamage). 

Fixed, Things mode: thing selection labels must be updated when performing undo/redo.
Fixed another case of invalid sectors being created after dragging map elements when using "Merge Dragged Geometry" and "Replace with Dragged Geometry" drag modes.

Added, Map Analysis mode: added "Edit Thing..." option to "Unknown Thing" and "Obsolete Thing" error check results.
Added: a warning is now displayed when a thing has both voxel and model attached.
Changed, Thing/Linedef Info panels: unknown ACS script names/numbers are now shown in red.
Fixed, Edit Things window, UDMF: unneeded undo was created when opening the window.
Re-fixed: in some cases invalid sectors were created after dragging map elements when using "Merge Dragged Geometry" and "Replace with Dragged Geometry" drag modes, when at least one of dragged linedef was facing into an enclosed void area (previous fix entirely disabled the associated logic).

Fixed: stored windows positions were not checked against current screen bounds, which may have resulted in windows being shown off-screen.

Fixed, Visual mode, UDMF: only the clicked floor/ceiling surface was dynamically updated when changing texture offsets of multiple floors/ceilings by mouse-dragging.

Merged "Toggle models, dynamic lights and fog rendering" and "Toggle Geometry Effects" actions into "Toggle Enhanced Rendering Effects" action.
Removed "Dynamic light size" and "Dynamic light intensity" settings.
Updated documentation ("Rendering toolbar" page).

Fixed, Visual mode: in some cases mouse cursor movement was not clipped to the render area when focusing the editor after Alt-Tabbing from the Visual mode.
Addressed, Line drawing: in some cases extra vertices were created when drawing lines on top of nearly parallel non-cardinal lines.

Updated, Visual mode, UDMF: "Change Texture Scale" actions now take camera and texture angles into account when used on floors/ceilings.
Changed: "+++" and "---" prefixes are now incremented on the first step instead of the second when used in any numeric inputs, which support prefixes, except action arguments.
Fixed, Visual mode, UDMF: texture offset/scale/rotation changes were applied several times when used on several 3d-floor floors/ceilings linked to the same control sector, when using "Move Texture Offsets" / "Change Texture Scale" / "Rotate Texture CW/CCW" actions.
Updated ZDoom ACC (DamageActor).
Updated ZDoom_ACS.cfg (DamageActor).

Added "localsidedeftextureoffsets" Game configuration setting. When set to true, enables in-editor support for individual offsets of upper/middle/lower sidedef textures. Affects UDMF map format only. - based on diff patch by Altazimuth.

Fixed several cases when certain texture manipulation-related actions caused a crash when performed on not-yet-loaded textures.

Fixed, Randomize things mode: fixed a crash when trying to move things, which were initially outside of sector boundary when using Hexen or UDMF map format.

Probably fixed probable I/O race condition when loading images.
Fixed Visual mode stuttering due to floating point precision degradation when running the editor for several days without restarting (internal timer is now reset when saving the map or creating a new one).
Fixed, Nodes Viewer, cosmetic: Nodes Viewer window position was reset after pressing the "Rebuild Nodes" button.
Added Eternity Game configurations by printz.
Updated ZDoom_ACS.cfg (CheckClass).
Updated ZDoom ACC (CheckClass).

Added, Visual mode: added support for "Change Floor Brightness to this Brightness" and "Change Ceiling Brightness to this Brightness" Boom actions.
Changed, Sectors mode: "Flip Linedefs" and "Align Linedefs" actions will no longer flip single-sided linedefs with only front side.
Fixed, Script Editor: fixed a crash when trying to update script navigator combo box when switching to a never saved ACS script.

Fixed, Visual mode: "Transfer Floor/Ceiling Brightness" actions were resetting sector color on target surfaces.
Updated ZDoom_DECORATE.cfg.

Fixed, Draw Geometry modes: fixed a crash when moving the mouse cursor over a vertex while holding Alt-Shift keys when there were no new points drawn in current mode.

Added "flagsrename" Game configurations property. It allows to override Thing flag names for specific things.
Added, Automap mode: added "Show locks" button (available in Hexen and UDMF map formats only).
Updated documentation.

Added, DECORATE: added "//$ArgNRenderStyle" special comment. It allows to specify a rendering shape to display the value of given argument. Supported values are "circle" and "rectangle".
Added, DECORATE: added "//$ArgNRenderColor" special comment. It allows to specify a color used by the rendering shape.
Updated documentation.

Added, Visual mode: added support for ROLLCENTER sprite rendering flag, updated ROLLSPRITE implementation.
Fixed, DECORATE support: the editor was unable to determine actor sprite when the actor itself had no sprites defined and the actor it inherited from was only defined in the game configuration.
Fixed, Drag geometry modes: linedefs without both sides were removed after dragging them when "Replace with Dragged Geometry" mode was active.
Updated ZDoom_DECORATE.cfg.

Added: preview sprites are now generated from voxels. Those are used as previews and when model rendering is disabled.
Fixed: voxel support logic was outdated, which in some cases resulted in voxels not being loaded and in some weird behaviour when trying to change pitch/roll of associated things.
Updated sprites lookup logic. Now it correctly handles sprites named like NNNNA0B0.
Fixed: in some cases DECORATE parser was unable to correctly detect sprite name & frame(s) block.
Updated ZDoom_ACS.cfg.
Updated ZDoom_DECORATE.cfg.

Fixed, Edit Selection mode, DB2 bug: in some cases "Flip Selection Horizontally" / "Flip Selection Vertically" actions were incorrectly flipping linedefs, resulting in broken sector geometry.

Visual mode: modified sidedef texture UV calculations to use integral linedef length to match (G)ZDoom way of rendering them.
Visual mode, UDMF: "Auto-align textures" actions now use integral linedef length when calculating texture offsets.

Added, Visual mode: added support for FLATSPRITE, ROLLSPRITE, WALLSPRITE and DONTFLIP sprite rendering flags. Removed the older GLOOME-specific implementation.
Changed, "Align Things to Nearest Linedef" action: the action can now also align things with FLATSPRITE and WALLSPRITE flags (previously only things with attached models were aligned).
Changed, "Align Things to Nearest Linedef" action: the action can now align things to the middle part of double-sided linedef, if it has a middle texture assigned. 

Added, Find & Replace mode, UDMF: added Linedef activation flags to the "Find Linedef flags" search mode flags list.
Changed, Sound Propagation mode: all sound zones are now shown when no sector is highlighted.
Changed, Sound Environments mode: the mode is now available only in UDMF map format.
Changed, Color Picker plugin: the plugin functionality is no longer available in Doom map format.
Restored the ability to create superimposed lines by dragging them with "Snap to Geometry" mode disabled.
Fixed, Sound Propagation mode: fixed a crash when a single-sided linedef had "Block Sound" flag.
Fixed, Find & Replace mode: in some cases "Find Sector/Sidedef/Linedef/Thing flags" search modes failed to find map elements with required flags.
Fixed, Edit Selection mode: in some cases incorrect geometry was created after applying multipart sector edit when "Replace with Dragged Geometry" mode was enabled.
Fixed a crash caused by eventual GDI font objects overflow.

Fixed, DB2 bug: temporary map file was growing in size after every map save/test, which eventually resulted in integer overflow exception when the file size reached ~2Gb.
Fixed, Draw Geometry modes: fixed a crash when moving the mouse cursor over a linedef while holding Alt-Shift keys when there were no new points drawn in current mode.