Error Check form: number of selected items is now shown in the window's title.
Error Check form: fixed slowdowns when trying to select many (like 1000) results at once.

Fixed, Sectors mode: selection info and highlight were not updated after using "Join Sectors" and "Merge Sectors" actions.
Linedefs mode: "Update 'lightfog' flag" was missing the click event handler.

Sector drawing: basic properties (textures, brightness, floor and ceiling height) are now taken from the nearest sector when a new isolated sector (e.g. a sector, which doesn't not intersect with already existing map geometry and is not inside of it) is drawn. 
Visual mode: when "Synch camera position" setting is enabled, and the cursor was outside of a sector when entering Visual mode, camera height is now adjusted based on nearest sector (previously the height was adjusted only when the cursor was inside of a sector).  
"Auto-align textures X", "Auto-align textures X and Y" actions, UDMF: alignment source sidedef part's horizontal scale is now applied to all aligned sidedefs.
Visual mode, UDMF: 'lightfog' flag is now automatically updated when changing sidedef brightness or using "Match Brightness" action. 
Linedefs mode: added "Update 'lightfog' flag" menu item.
Game configurations: cosmetic changes in UDMF linedef flag names.
Updated ZDoom_DECORATE.cfg.

Fixed, Visual mode, 3D floors: in some cases 3d floor flags were handled differently than in GZDoom.

Fixed, Edit Selection: in some cases thing angles were updated incorrectly when things with "FixedRotation" game configuration property were among selected things.
Fixed, Visual mode: floor brightness was calculated incorrectly when "Disable Light Effects"/"Restrict light inside" 3d floor flags were used and the floor had "lightfloor" property.
Fixed: "lightabsolute" flag was accessed incorrectly in previous commit.

Fixed, long texture names support: in some cases long texture names were not processed correctly when pasting map geometry.
Fixed, Visual mode: in some cases combined sidedef brightness was calculated incorrectly. Also, MAPINFO FadeColor and OutsideFogColor properties are now taken into account.
Hexen_linedefs.cfg: "Door Raise" and "Door Locked Raise" used incorrect enums for "Close Delay".

Updated documentation.

ZDoom_linedefs.cfg: "Plane" actions don't require activation.

Visual mode, "Raise Floor/Ceiling to adjacent sector", "Lower Floor/Ceiling to adjacent sector": things with "absolutez" flag should be handled differently. 

Fixed, Visual mode: in some cases "Raise Floor/Ceiling to adjacent sector" was not working properly when used on things.

Fixed, Visual mode: a case when thing's height was bigger than distance between floor and ceiling's planes is now handled the same way as in ZDoom.

Fixed, Visual mode: when thing's position is not absolute, it should always be positioned between floor and ceiling planes.

Sound Environment mode: you can now add sound environment things using "Insert Thing" or "Edit Selection" actions (just like you add things in Things mode).
Sound Environment mode: you can now delete currently highlighted sound environment thing by using "Delete" action.
Sound Environment mode: the sidebar panel icons now have the same colors as corresponding sound environments.
Fixed, Sound Environment mode: in some cases several sidebar panel items were highlighted at once (I broke this in r2201).
Fixed, Fit Textures action: lower linedef parts were aligned incorrectly.
Changed, Fit Textures Options form: "Fit across multiple surfaces" checkbox is now disabled when the action is applied to a single surface.

Fixed, Sectors Mode, UDMF: "Make Brightness Gradient" action was not working when "Sector Brightness" mode was selected... 

Visual mode, UDMF: renamed "Scale Texture Up/Down (X/Y)" actions to "Increase/Decrease Horizontal/Vertical Scale". These actions can now be used on things.

Fixed, DECORATE parser: "scale", "xscale" and "yscale" properties are now parsed the same way as in ZDoom.
Fixed, DECORATE parser: parser was unable to parse negative numeric properties.

Fixed, Texture previews: texture size labels were displaying incorrect size or no size at all when showing TEXTURES textures with negative scale.
Fixed, Visual mode, UDMF: when several wall parts were selected, only one could be dragged with the mouse.
Fixed, Visual mode, Auto-align textures, UDMF: TEXTURES scale is now taken into account when aligning textures.
Fixed, Visual mode, Auto-align textures (Y), UDMF: nearest height matching is now applied to non-wrapped middle backsides.
Cosmetic changes in ZDoom_ACS.cfg.

Linedef/Thing Edit forms: cosmetic changes to named/numbered script drop-down locations.

Changed, Edit Sector/Linedef/Thing/Vertex forms: undo is now created either when user changes a value using a real-time control or when applying changes, not when opening a form.

Updated ZDoom_DECORATE.cfg.

Changed, Sound Environment mode: on second thought, we don't need to scan all map things to find one to highlight...

Sound Environment Mode: sound environments can now be picked by editing sound environment things.
Sound Environment Mode: detected sound environments names are now used as item names in the tree view.
Fixed, Classic modes: incorrect texture was used as unknown floor/ceiling texture (I broke this in r2199).
Fixed, MainForm: reverted MainForm.UpdateToolStripSeparators. By making it look simpler I made it work more buggy...
Updated ZDoom_DECORATE.cfg.

Fixed: flats and textures defined in TEXTURES should override regular ones (adding long texture names support broke this).
Removed unused references from all projects.

Changes since 5bf51d0:
Large scale cleanup & refactoring.
Sound Propagation Mode: you can now click on doublesided linedefs to toggle sound blocking flag.
Sound Environment Mode: you can now click on doublesided linedefs to toggle sound zone boundary flag.
Sound Propagation Mode: reimplemented the highlighting of non-deaf things. Things are now highlighted using selection color.
Removed "Show tooltips" checkbox. Tooltips are now always enabled.
Fixed, Sound Environment Mode: thing tooltip about multiple active sound environment things was shown even when there was only one active sound environment thing.
Fixed, Sound Environment Mode: "Configure colors" toolbar button was not working because of missing action.
Fixed, cosmetic: "Configure colors" toolbar icon was missing a tooltip.
Fixed, cosmetic: display was not redrawn after changing colors using "Color configuration" window.

Fixed, Thing Browser Control: "Multiple Things" icon was assigned to BackgroundImage instead if Image.
Updated ZDoom_DECORATE.cfg.

Fixed, Script Editor: named scripts were not shown in the script navigator drop-down when current map was not in UDMF.

Changed, Script Editor: changed text cursor behavior when selecting an item in the script navigator drop-down to Visual Studio-like.

Moved stuff around a bit in PK3Reader. Will it fix random crashes? I dunno, a least I was no longer able to trigger them...
Recompiled SharpCompress library using VS 2008, so it no longer references .net 4.0 stuff. Will it fix random crashes? See above.

Visual mode: "Auto-align textures" actions now align mixed textures when used on a selection (helpful if you want to align several different textures, which can tile into each other).
Cosmetic: errors and warnings are now cleared when reloading resources. 

Script Editor: fixed an exception when a script configuration contained identical keyword and constant.
ZDoom_DECORATE.cfg: added a bunch of actor properties.

PK3Reader: probably fixed a random sharpcompress crash when trying to access a closed file (totally unsure, need more testing).
ZDoom_linedefs.cfg: fixed a typo.

ZDoom_misc.cfg: added an empty "spawn_projectile" enumeration to prevent warnings when game-specific enums group doesn't contain this enum.
Game_Chex.cfg was misplaced.

Fixed, Sectors mode, UDMF: surface cache was not updated after applying floor/ceiling brightness gradients.
Cosmetic, Sectors mode, UDMF: brightness gradient modes now have more descriptive names.
Internal, InterpolationTools: replaced EaseInOutSine equation with one, which actually works.

Sectors mode: "Gradient Interpolation Mode" toolbar menu.
Internal: extracted easing functions from Bridge Mode into InterpolationTools class.
+a couple of cosmetic changes.