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).
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, Classic modes: MODELDEF model scale was not taken into account when calculating model visibility, which resulted in models with increased scaled disappearing when near screen edges.
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.
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.
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.
DECORATE: added "//$ArgNEnum" special comment. It can be used to specify an enum to use with the argument.
Documentation: updated "Action Argument Settings" and "DECORATE keys" pages.
Game Configurations: updated things in ZDoom "Bridges" category to use argument types 23 and 24.
Documentation: added "Action Argument Settings" page, updated "Basic Settings", "Map Format Settings", "Linedefs Settings" and "Things Settings" pages in Configurations -> Game Configurations group.
Documentation: updated "DECORATE keys" page.
Sector Edit Form, UDMF: Sound Sequence selector is now a drop-down populated by values parsed from SNDSEQ.
Documentation: updated "(G)ZDoom text lumps support" page.
Updated udmf_zdoom.txt.
Fixed, Game Configurations window: current map is marked as changed when applying changes done in the window.
Changed, UDMF saving: removed extra line break between map elements.
