Things mode: added Filter Selection form (Things -> Filter Selection), which allows to quickly filter selected things by type.
Tag Statistics form, Thing Statistics form: fixed a crash when clicking on table's header cells.

One of Thing Statistics form's columns was editable for no good reason.

UDMF: sector, linedef and thing render styles are now defined in Game Configuration.

Randomize mode: randomized pitch, roll and scale can now be applied to things.
Randomize mode: removed "Relative" option, because results with this option enabled were almost the same as without it.
Classic modes, model rendering: selected models are now rendered using highlight color, so they no longer blend with thing rectangle/circle.
Model rendering, UDMF: scale was applied incorrectly to models with pitch or roll.
Updated documentation.

Thing Edit form, UDMF: default value of pitch and roll angle controls is now up.
Angle control: direction line is not displayed when showing mixed values.

Moved "Action Doom", "Harmony", "Chex Quest" 1 and 3 game configuration to Configurations/Other Games.

Thing Edit Form, UDMF: added controls for setting pitch, roll, scale, render style, fill color, alpha, health and score.
Visual mode, UDMF: UDMF scale is now applied when rendering sprites.
Added Thing Statistics form (Edit -> View Thing Types...), which shows all loaded thing types with some additional info.
Visual mode: sprites with negative ScaleX and positive ScaleY were not rendered properly.
Classic modes: display was not updated after loading a sprite.
Current testing engine change was not saved on closing the program when no other game configuration settings were changed.

Things mode: you can clone selected/highlighted things by holding "Shift" before starting to drag them.

Added "Paste Properties Options" form, which lets you pick properties for 'Copy Properties' and 'Paste Properties' actions.
Removed CopyPasteSectorProperties plugin, because built-in "Copy/Paste Properties" actions do the same job, but better.

"Rotate Clockwise" and "Rotate Counterclockwise" actions now work in Things mode (they will rotate things) and in Sectors mode (they will rotate floor/ceiling textures based on current view mode).
Moved "Rotate Clockwise" and "Rotate Counterclockwise" actions to "Edit" category.
Tag Statistics form: help label was incorrectly aligned.
Some actions in Sectors and Linedefs modes were not used on highlighted map elements.
Some actions in Sectors and Linedefs modes created undo groups incorrectly when used on highlighted map elements.

Fixed: .dbs map configuration was not loaded when loading a map by dragging a wad file on top of GZDB shortcut/executable.

"Preferences -> Editing -> When splitting a linedef" setting is now always used when splitting linedefs.
"Preferences -> Editing -> When splitting a linedef": added "Reset X and Y" option.
"Preferences -> Editing -> Auto-align textures of newly created linedefs" option now works in a more intelligent fashion.

Replaced a couple of internal thing sprites.

Replicated Doom texture vertical offset glitch when front and back sector's ceilings are sky.

GLDEFS parser: made dynamic light attaching rules a bit stricter. Now a light is attached to an actor if frame length is 4 chars or 5-th char is 'A' in GLDEFS object definition.

GLDEFS parser: added a warning when the interval of animated dynamic light is 0.
Visual mode: fixed a crash when an angle of animated dynamic light was set to 0 and light animation was enabled.
Tag explorer: removed unnecessary mode switching when selecting map elements of the same type.

+ couple of cosmetic fixes.

Moved all Skulltag things, which are no longer available by default in Zandronum, to Skulltag_things.cfg
Zandronum configs no longer require additional resources to load without errors.

Make Door action: door and track textures are now stored while the editor is running.
Edit Selection Mode: pasted geometry was not merged with the rest of the map if the selection was not modified before applying the mode.

Make Door action: made Make Door form a bit smaller.
Make Door action: sector highlight was not updated after performing the action when a single sector was selected.

Linedef Edit Form, Sector Edit Form: when several map elements with different textures are selected, the "texture stack" icon is shown in the texture selectors instead of the "missing texture" icon.
Error Checker mode: added "Check missing flats" check.
Error Checker mode: fixed several descriptions. 
Sprite patches for sprites defined in TEXTURES are now loaded from Sprites namespace.
Some of my older texture alignment code didn't work properly when strict texture/flat handling ("mixtextureflats" game configuration flag set to false) was enabled.
Fixed some incorrect checks for missing texture ("-").

Buttons order was messed up in editing modes toolbar after performing "Reload Resources" action.
Fixed editing modes toolbar layout.

Fixed a crash when using "Reload GLDEFS" and "Reload (Z)MAPINFO" actions when GLDEFS / MAPINFO file was moved or renamed after opening the map in the editor.

Added "Full Brightness" toolbar button and "View" menu item. These call "Toggle Full Brightness" action.
Added "Make Door" menu item to "Sectors" menu.
A warning is now displayed when "Make Door" action is called without a selection.

Moved settings for "Draw [stuff]" modes to the top toolbar.
Added hints for Draw Grid mode.
Fixed a status message update bug introduced in previous commit.