Internal: Scrollbar: Further sane simplification (using InnerMainRect instead of duplicating calculations).

Separator: Revert 1.70 "Declare its thickness (1.0f) to the layout" change (c5d83d8a). It's not incorrect but it breaks existing some layout patterns. Will return back to it when we expose Separator flags.

Internal: Refactored Separator into SeparatorEx(), exposed ImGuiSeparatorFlags_SpanAllColumns in imgui_internal.h and support without. (#759) + misc comments

Columns: Fixed Separator from creating an extraneous draw command. Fixed Selectable with SpanAllColumns flag from creating an extraneous draw command. (#125)

Version 1.71 WIP + fixed minor typo

Version 1.70

Examples Readme and Changelog tweaks, added #2527, re-ordered examples/README alphabetically.

Window: Fixed SetNextWindowSizeConstraints() with non-rounded positions making windows drift. (#2067, #2530)

Misc: Made IMGUI_CHECKVERSION() macro also check for matching size of ImDrawIdx.

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)