Selectable: With ImGuiSelectableFlags_AllowDoubleClick doesn't return true on the mouse button releas efollowing the double-click. Only first mouse release + second mouse down (double-click) returns true. Likewise for internal ButtonBehavior() with both _PressedOnClickRelease | _PressedOnDoubleClick. (#2503)

Demo: Improved trees in columns demo. (#2136)

ImDrawCallback_ResetRenderState: Added Metal.

ImDrawCallback_ResetRenderState, Examples: Added support for reset render state callback. (#2037, #1639, #2452)

Obsoleted GetContentRegionAvailWidth(), use GetContentRegionAvail().x instead. Kept inline redirection function.

Drag and Drop: Fixed drag source with ImGuiDragDropFlags_SourceAllowNullID and null ID from receiving click regardless of being covered by another window (it didn't honor correct hovering rules). (#2521)

Amend 48a09a7 with changelog, breaking changes, tweak demo code for spacing. (#2518)

Popups: Closes popup at the time of FocusWindow(). Fixes right-click from closing all popups instead of aiming at the hovered popup level (regression in 1.67's ae76a1fd).

Popups: Closing a popup restores the focused/nav window in place at the time of the popup opening, instead of restoring the window that was in the window stack at the time of the OpenPopup call. (#2517) ...

Among other things, this allows opening a popup while no window are focused, and pressing Escape to clear the focus again.

Window: Fixed contents region being off by WindowBorderSize amount on the right when scrollbar is active.

Separator: Declare its thickness (1.0f) to the layout, making items around separator more symmetrical.

Nav: Fixed Drag/Slider functions going into text input mode when keyboard CTRL is held while pressing NavActivate.

Internals: TempInputText: Rename InputScalarAsWidgetReplacement() -> TempInputTextScalar(), ScalarAsInputTextId -> TempInputTextId, small tidying up in affected functions.

Window: Fixed window with the AlwaysAutoResize flag unnecessarily extending their hovering boundaries by a few pixels (this is used to facilitate resizing from borders when available for a given window). One of the noticeable minor side effect was that navigating menus would have had a tendency to disable highlight from parent menu items earlier than necessary while approaching the child menu. ...

+ Changelog fixed unfinished sentence and tweaks,

Misc comments, internal renaming, added disable indentation option to Columns demo section.

Examples: SDL: Gamepad support minor amend. Fixes ImGuiBackendFlags_HasGamepad not being set. Enable in Emscripten demo. Tweaks. (#2509, #2484).

Added SetNextItemWidth() helper to avoid using PushItemWidth/PopItemWidth() for single items.

Misc: Fixed PushItemWidth(-width) (for right-side alignment) laying out certain items (button, listbox, etc.) with negative sizes if the 'width' argument was smaller than the available width at the time of item submission,

Combo, Slider: Improve rendering in situation when there's there's very little space available.

Columns: Fixed boundary of clipping being off by 1 pixel within the left column.

Clarified asserts comments + todo entries. (#2500)

Metrics: Added "Show windows rectangles" tool to visualize the different rectangles.

Merged a bunch of small changes from Docking branch to reduce the difference between branches. ...

Noticeable: horizontal alignment of CloseButton. Menu fill take account of border. Various stylistic tweaks to accomodate other changes in Docking.

Examples: DirectX10/11/12, Allegro, Marmalade: Render functions early out when display size is zero (minimized). (#2496)

Examples: Visual Studio: Updated default platform toolset+sdk in vcproj files from v100+sdk7 (vs2010) to v110+sdk8 (vs2012). This is mostly so we can remove reliance on DXSDK_DIR for the DX10/DX11 example, which if existing and when switching to recent SDK ends up conflicting and creating warnings.

Examples: Emscripten: Switched to WebGL1/ES2, Added Changelog, Updated links, Added ignore list, Fixed warning with older versions. Removed reliance on C++11 (would warn on some compiler). Improved html template, removed undesirable options, reduced log size. Tweaked main.cpp. (#2494)

PlotLines, PlotHistogram: Ignore NaN values when calculating min/max bounds. (#2485)

Internals: Tweak ItemSize calls. Added todo items.

Merge branch 'vulkan_fix_master'

FAQ tweaks. Add missing entries in imgui.cpp (which until now where only in the README).