Resource List Editor: not existing resources are now shown using different color. 
Map Options, Open Map Options, Game Configurations windows: a warning is now shown when a map resource doesn't exist.
Some minor fixes to Resource List Editor's context menu.
Updated ZDoom_DECORATE.cfg.

Resource List Editor: fixed potential crash on pasting/replacing resources when there are duplicate resources in the list.
Resource List Editor: duplicate resources are no longer added when adding resources using drag and drop.

Resource List Editor now has a context menu.
Fixed misleading warning asking user to install DirectX when unable to detect SlimDX.

Rendering: mode fixes to MODELDEF and UDMF properties-related model rendering logic.

Fixed, Rendering: MODELDEF RollOffset, AngleOffset, Scale and ZOffset properties were applied incorrectly.
Fixed, Rendering: VOXELDEF Scale property was applied incorrectly.

Import Wavefront .obj as Terrain mode: floor height of each created sector is now set to the average height of an .obj polygon it was created from.
Import Wavefront .obj as Terrain Settings window: added "Use slopes" checkbox. When enabled, the mode will create slopes using vertex height offsets (UDMF) or Floor Vertex Height things (1504).
Fixed, Visual Mode: things were rendered at wrong height after using "Lower/Raise Height" actions in sectors with sloped floor (or ceiling for ceiling-aligned things) 
Fixed: info panel was not updated after switching to another Edit Mode.

Find and Replace window: added "Find Previous" button.

Script Editor: expanding snippet by pressing the Tab key now works only when the text cursor is at the end of a keyword.
Updated ZDoom ACC.
Updated ZDoom_things.cfg.
Updated documentation.

Bit Flags form now changes width to show flags with long names without scrolling.
Bit Flags form: flag numbers are now shown as well as names.
Game configurations: updated Hexen and ZDoom linedef definitions. Now they (hopefully) fully match ZDoom ones. 
Action Selector Control: fixed a crash when trying to increase action above maximum value using mouse wheel.
Sector/Linedef/Thing tag lists are now handled by corresponding TypeHandlers (and not by dirty hacks as before).
Linedef info panel: line peggedness labels were obscured by effect label in Doom/Hexen map formats.

Thing\Linedef Edit Form: added some tooltips.
Some cosmetic layout changes in LinedefEditForm.

Cosmetic changes in Sector Info Panel and Thing Browser Control.
ArgumentInfo: fixed a crash when enum specified in a game configuration doesn't exist.
Updated Hexen and ZDoom linedef configs.
Updated ZDoom_DECORATE.cfg

Thing, Sector, Linedef edit forms, UDMF: fixed more cases when missing game configuration blocks crashed the forms.
Thing and Sector edit forms, UDMF: fixed some minor layout issues.

Fixed, Texture Browser form: we should not save "Long texture names" value when Map.Config.UseLongTextureNames is disabled.
Fixed, Linedef Edit form (UDMF): fixed a crash on opening the form when "linedefrenderstyles" block was missing from game configuration.

Texture Browser Control: "Long texture names" and "Show image size" values are now stored in program configuration.

Fixed, Texture Browser Form: well, I broke "Tab" key functionality again (in previous commit)...
Maintenance: changed curly braces style to match DB2 one (hopefully not breaking anything in the process...).
Maintenance: changed private method names casing to match DB2 one.

Texture browser form: added "Long texture names" check-box. It can be used to toggle between displaying long and short texture names.
Texture browser form: added "Show image size" check-box.
Texture browser form: image size is now shown differently.
Image Selector: added a button to toggle between long and short texture name.
Linedef info panel: long texture names are now displayed properly.
Sector info panel: long texture names are now displayed properly.
Fixed: "Save Screenshot" and "Save Edit Area Screenshot" actions were triggered multiple times when a child window was open.
Fixed: used textures should be always updated after using "Change map in current WAD" action.
Fixed, "Change map in current WAD": fixed a crash when trying to switch from a map with missing game configuration path.
Updated ZDoom_ACS.cfg.

Added long texture names support (enabled when "longtexturenames" game configuration property is set to true and "Use long texture names" check box is checked in Map Options).
Open Map in Current WAD: resources are now reloaded when current and target map's resources don't match.
Added some boilerplate to UniversalParser and PK3FileImage.
Internal: ImageSelectorControl now has "UsePreviews" property.
Internal: added ConfigurablePictureBox.
Updated ZDoom_DECORATE.cfg.

Linedef Edit Form, UDMF: "Lock number" now has a drop-down with supported key types (no LOCKDEFS support (yet?)). You can still type lock number manually.

Internal: removed some unrelated stuff from NodesViewer.csproj.

Thing Edit form: when selection contains more than one thing, thing types form selected category are now randomly applied to it.  
Fixed, Thing Edit form: selection change was not processed in some cases.

Changed: thing sprite is now displayed in ThingBrowserControl.

"Find Any Texture or Flat", "Find Sector Flat" and "Find Sidedef Texture" options now support "*" (match any number of characters) and "?" (match any single character) wildcards.
"Find Any Texture or Flat" is now available any game configuration (previously it was disabled when "MixTexturesFlats" game configuration option was disabled, now only "Replace" functionality is disabled).
"Find Thing Flags" and "Find Linedef Flags" can now replace flags.
Added "Find Sidedef Flags" and "Find Sector Flags" search options.

Fixed, Draw Grid mode: fixed a crash on accepting the mode when start and end points had the same coordinates.
Fixed, Draw Grid mode: grid triangles are now aligned properly with previously drawn triangulated grids when using the same map grid size and "Lock slices to grid" and "Triangulate" options are enabled.
Fixed, Draw Grid mode: not all grid cells were drawn in some cases.
Fixed, Draw Grid mode: current grid size was not increased when "Lock slices to grid" was enabled and the start point was no longer on the map grid.
Changed, Draw Grid mode: snap to grid is now always enabled and snap to nearest is now always disabled when "Lock slices to grid" is enabled.
Changed, Draw Grid mode: when grid's width or height is 0 when accepting the mode, a segmented line is now drawn instead of just a line.

Fixed, Open Map form: a warning is now displayed when no map is selected when accepting the form.

Fixed, Thing edit form: implemented overcomplicated required flags check (which should work as expected this time. probably.).

Fixed, Change Map form: keyboard focus was not properly updated after selecting current map in the maps list.

Fixed: when switching to a different map format, all nodes with "nodebuild" property set to true in the "maplumpnames" block of current game configuration are now removed.

A warning is now displayed when an unclosed marker range is found in a WAD (e.g. when there's a S_START, but no S_END after it).

Fixed incorrect screenshot size when a window was maximized.
Fixed: more than one screenshot per second can now be saved.
Changed screenshot filename date format to yyyy.mm.dd.