Fixed, DB2 bug: side panel's tabs were drawn incorrectly when panel's height was lower than cumulative tabs height.
Visual mode, GLOOME: wall/floor/ceiling sprites are now rendered closer to the way it's done in GLOOME.
Sectors mode, UDMF: some cosmetic tweaks to comment icons rendering.
Classic modes: linedef rendering is now skipped when it's visible length is very short.
General interface: fixed a possible crash when clicking on the warnings count label when it was updated from the background thread.

Fixed, Visual mode: texture coordinate generated to test if double-sided middle texture is transparent was shifted 1 pixel up.
Fixed, Visual mode: offsets of GLDEFS lights were not affected by thing's angle.
Updated SharpCompress (0.10.3 -> 0.11.1).
Updated ZDoom_DECORATE.cfg.

Removed Trackbar.dll.

Changed, Visual mode: changed thing fog calculation logic. Should be closer to GZDoom now.
Fixed, GLDEFS parser: "height" texture parameter was not treated as optional.
Fixed, text lump parsers: in some cases incorrect line number was displayed in error and warning messages.
Fixed, Visual mode: glow effect was not applied to sectors with 3 sidedefs.
Fixed, Visual mode: in some cases glow effect was not updated when replacing textures. 
Fixed, general interface: "Full Brightness" button state was not updated during map loading.
Fixed, Drag Linedefs/Vertices/Sectors/Things modes: positions of line length labels were not updated while panning the view.
Cosmetic: added a bunch of new icons.
Cosmetic: changed Visual mode crosshair.

Changed, Drag Linedefs/Vertices/Sectors/Things modes: line length labels are now displayed the same way as in Draw modes.
Changed, Drag Linedefs/Vertices/Sectors/Things modes: "lock movement to cardinal directions" mode (Alt-Shift-Drag) now locks movement in 4 directions instead of 8 and doesn't snap map elements to nearest grid intersections when they are not aligned to it. 
Added, Visual mode, GZDoom, DECORATE: FORCEXYBILLBOARD flag is now supported.
Added, Visual mode, GLOOME, DECORATE: FLOORSPRITE, CEILSPRITE, WALLSPRITE, ROLLSPRITE and STICKTOPLANE flags are now supported (implementation is somewhat broken ATM and probably doesn't work the same way as in GLOOME, because Windows build with most these features is nowhere to be found...).
Fixed, Visual mode: in some cases Thing brightness was calculated incorrectly.
Updated ZDoom_DECORATE.cfg.

Changed, Draw Lines/Rectangle/Circle/Curve modes: line length labels are now repositioned to stay on screen when line's start or end is not visible.
Added, Map Analysis mode: added "Check map size" check. It will generate a warning when map's width or height is larger than 32767 m.u.

Added, Things mode, Visual mode: event lines for InterpolationPoints are now curved when appropriate setting is enabled in the control thing (PathFollower/ActorMover/MovingCamera) [heavily inspired by Xabis' patch].
Added, Things mode: the editor will try to reconnect the path when deleting InterpolationPoints and PatrolPoints.
Internal: RenderArrows method now works the same way in Renderer2D and Renderer3D.
Internal: Line3D now has "renderarrowhead" property.

Added, Things mode: target tags are now automatically assigned when duplicating (shift-dragging) PatrolPoints and InterpolationPoints.
Fixed, ThingsMode: fixed highlighted thing disappearing when using paste action while highlighting a thing.

Classic modes: added "Toggle Grid" action (default key is Alt-G), new menu item in the View menu and new toolbar button.
Changed, Things mode, cosmetic: tweaked thing sprite/bounding box appearance a bit more...
Fixed, Linedefs mode, cosmetic: fixed event lines and sector highlights flickering when view panning was started while displaying action highlight.

Changed, Things mode: things are now rendered with a bit of transparency, so things beneath other things are now visible.
Fixed, Things mode: in some cases it was impossible to highlight a thing beneath other thing when their positions were the same.
Changed, 2D modes: changed thing bounding box and arrow image.
Fixed, cosmetic, 2D modes: in some cases thing arrows were rendered bigger than thing bounding boxes.

UDMF: most of the code now supports multiple sector/linedef tags ('moreids' UDMF property). The only things left out are Tag Explorer and Tag Range plugins.

Fixed, Edit Selection mode: "High precision positioning" setting was set to false after using the mode in non-UDMF map format.

Fixed, Classic modes, Visual mode, UDMF: the last argument of Sector_Set3dFloor (160) action must be ignored in UDMF.

General interface: selection info is now always displayed.
Visual mode: you can now hold Alt-Shift or Ctrl-Alt while selecting sidedefs to stop selecting connected sidedefs when already (un)selected sidedef is encountered.
Added, Numeric Textbox: you can now use "+++" and "---" prefixes to incrementally increase or decrease result values by given value.
Fixed, Numeric Textbox: fixed a potential divide by zero exception when using "/" prefix in numeric textboxes with decimal input enabled.
Fixed, Thing Info panel: relative z position of things with "+SPAWNCEILING" flag was incorrect.
Changed: Update checker now displays messages using MessageBoxes when called manually.
Map Analysis: changed result descriptions for Unknown Texture and Missing Texture checks.
Doom map format: renamed "Secret" linedef flag to "Shown as 1-sided on automap".
Updated ZDoom_DECORATE.cfg (A_RadiusGive stuff).

Added some boilerplate to CommentsDocker.
Internal: converted a bunch of if-elses to switches.

Sectors, Linedefs, Things modes: comment icons for appropriate map elements with comments are now rendered in these modes. This can be disabled using either the new "Toggle Comments" action, "View -> Show Comments" menu item, or "Show Comments" button on the main toolbar.

Changed, Edit Text window: the form is no longer accepted when pressing the Enter key, so line breaks can now be added easily.
Versioning: GZDB version is now determined by the first 2 revision digits, so now it's GZDB 2.3, not 1.14.

Map Analysis mode: added "Check very short linedefs" check (unchecked by default), which finds linedefs shorter than 1 m.u.
Fixed: script editor must be closed during "Open map in current WAD" action.
Added: PNG offsets are now taken into account when loading sprites.

Changed: current 2D position and zoom is now stored in the .dbs file when saving the map and restored when opening it (should this be turned into toggleable option?).
Draw Lines mode, Draw Curve mode: you can now hold Alt - Shift to snap to 8 cardinal directions.
Draw Rectangle mode, Draw Grid mode: you can now hold Alt - Shift to draw square shapes.
Draw Ellipse mode: you can now hold Alt - Shift to draw circle shapes.
You can now hold Alt - Shift to snap to 8 cardinal directions while dragging map objects.
Fixed, Draw Lines mode: line angle is now displayed in 0..359 range (was -45..314).
Fixed, Linedef info panel: line angle is now displayed in 0..359 range (was -45..314).

Fixed, Texture Browser: in some cases the control was unable to select proper texture by short name when long texture names support was enabled.
Sound Environments mode: sound environments list is now sorted.

Fixed, Sound Environments mode: fixed an exception when clicking on already selected child node in the sound environments list (I broke this in the previous commit).
Fixed, Sound Environments mode: the view now centers on selected sound environment when clicking on a sound environment in the list (I broke that when I've added proper sound environment names way back when).

Changed, Classic modes: model wireframe is now rendered using Highlight color when corresponding thing is highlighted (and Select color when it's selected).
Sound Environment mode: added "Show nodes with warnings only" checkbox to the panel.
Sound Environment mode: somewhat increased sound environment update speed by updating the list after all sound environments are updated.
Sound Environment mode: the list now scrolls to show highlighted sound environment.
Sound Environment mode: sound environments can now be (de)selected. Selecting a sound environment stops highlighting sound environments / scrolling the list when moving the mouse.

Fixed incorrect formatting of changelog messages displayed in the updater window.
Changed, Classic modes: models for things hidden by thing filter are now rendered with much lower alpha than the "regular" ones.

Changed, Sound Environments mode: previously selected sound environment is now automatically selected when inserting a new sound environment item. Also it's now impossible to accept the form without selecting a sound environment.
Changed, Sound Propagation mode: single-sided lines with sound zone boundary flag are now highlightable and clickable.

Fixed, Wavefront .obj Export: long texture names were handled incorrectly causing exceptions during textures export.

Fixed, Linedefs mode, since r2346: some event lines were not redrawn when updating insert vertex preview. 

Classic modes: changed the way event lines are rendered. Should work much faster now. Event lines are now displayed while panning the view.

Fixed, Visual mode, "Auto-align textures" actions: auto alignment was applied incorrectly to middle parts of doublesided lines.
Fixed, Visual mode, "Auto-align textures" actions: in some cases generated texture offsets were not rounded to map format decimal number precision.

Edit Selection mode, UDMF: added "High precision positioning" setting. When enabled, thing and vertex positions will be set using floating point precision. Otherwise, they will be rounded to the nearest integer.

Fixed, Edit Selection mode: floor/ceiling textures rotation was not converted from radians to degrees when "Transform Texture Rotation" setting was disabled.

Fixed, Visual mode, since r2336: in some cases local vertical texture offset was calculated incorrectly when checking sidedef's texture alpha.

Fixed, Visual mode, UDMF: in some cases texture offsets were changed incorrectly while dragging sidedefs with negative texture scale.

Changed, Linedef Edit window, Visual mode, UDMF: when "Edit windows remember selected tabs" setting is enabled and Front or Back tab was previously selected, the tab, which corresponds to the highlighted side will be selected.

Fixed, Visual mode: z position of info lines for polyobject setup things was calculated incorrectly.
Updated ZDoom_DECORATE.cfg.

Added: nested thing categories can now be defined in DECORATE using "//$Category" special comment. Syntax is the same as in SLADE 3.
Added: thing categories defined in Game Configurations can now be nested.
Changed, Thing Edit window: thing categories now use different icons.
Fixed: Thing Edit and Vertex edit windows had incorrect help links.
Fixed: Sound Propagation and Sound Environment modes had incorrect help links.
Documentation: updated "DECORATE keys" and "Things Settings" pages.

Added, Edit Selection mode, UDMF: textures offset, rotation and scale an now be updated while using the mode.
Documentation: updated "DECORATE keys" page.

DECORATE: added "//$ArgNDefault" special comment. It can be used to specify the default argument value.
Visual mode, 3d floors: sloped 3d floors are now always rendered as opaque (just like in GZDoom).
Fixed a crash when creating a new unknown thing (introduced in r2324).
Documentation: updated "Action Argument Settings" and "DECORATE keys" pages.