Internals: Tracking dummy select scope id (currently always zero) to facilitate merging of the range_select branch. (#1861)

Internals: Track ActiveIdHasBeenPressed (similar to ActiveIdHasBeenEdited). This is currently mostly for the benefit of the range_select branch. (#1861)

Merged from Docking branch: Various small changes, comments, typos fixes, moved blocks. To reduce overall drift. Should be no-op.

InputText: Fixed a bug where ESCAPE would be first captured by the Keyboard Navigation code. (#2321, #787)

imgui-test: Added extra item info callbacks. Using nav_bb for interactions when possible. Comments, Demo tweaks.

Fix various XCode and PVS-Studio static analyzer warnings (#2309)

Fixed range-version of PushID() and GetID() not honoring the ### operator to restart from the seed value.

Removed trailing spaces (#2038, #2299)

Added checks for "zero-as-null-pointer-constant" warnings for older Clang (#2299, followup to #2277)

Version 1.68 WIP

TODO update + internals: changed order or ImGuiLayoutType enums to allow using them for indexing.

Version 1.67

Added a bunch of diagnostic ignore to cope with Clang -Weverything being absurd. Also fixed two legit warnings. (#2277)

ImFontAtlas: Rewrote stb_truetype based builder. ...

- Atlas width is now properly based on total surface rather than glyph count (unless overridden with TexDesiredWidth).
- Fixed atlas builder so missing glyphs won't influence the atlas texture width. (#2233)
- Fixed atlas builder so duplicate glyphs (when merging fonts) won't be included in the rasterized atlas.

Internals: Added ImBoolVector helper.

ImVector: Made a struct. Using T/T* in the code instead of value_type/iterator. Renamed index_from_pointer() to index_from_ptr() (was not documented, added in 1.63, users not supposed to use ImVector, hopefully not a big deal).

Internals: Added comment index in imgui_internal.h

Internals: LowerBound: Use raw pointer typedefs, we never use iterator anywhere else in the codebase. ...

Demo: Typo.
C98 fix.

Tests: Reworking hook prototypes for imgui-test to be faster and multi-context friendly.

Selectable() should have an ID even though they are disabled, to be consistent with other widgets. Not sure of the reasoning ~1.41 which made this turn to 0.

Fixed animated window titles from being updated when displayed in the CTRL+Tab list. + Adding overkill helpers for reusing buffers. (#787)

Tweak changelog + tweak internal render helper functions.

Added bindings in Readme. Added internal IMGUI_DEBUG_LOG() helper. Comments, missing breaking changes note relative to imgui_impl_xxxx changes, not really part of core but worth adding in the imgui.cpp breaking change section.

Internals: Extracted code out of EndFrame() into UpdateMouseMovingWindowEndFrame()

Alternative fix for bug introduced in d845135 (#1651), fix CTRL+Tab and fallback tooltip.

Window, Focus, Popup: Fixed an issue where closing a popup by clicking another window with the _NoMove flag would refocus the parent window of the popup instead of the newly clicked window.

Internals: Popups: Renamed CurrentPopupStack to BeginPopupStack which is much less ambiguous.

Internals: Popup related comments. Renamed the misleading internal ClosePopup() function. Added bool* test to BeginPopupModal in demo.

Tests: Changed prototype of ImGuiTestEngineHook_ItemAdd to match functions called in same spot. Made ButtonBehavior submit fallback item info if ItemAdd() was not called (for resize grips, resize borders, scrollbar, columns, etc.)

Added BETA api for Tab Bar/Tabs widgets. (#261, #351) (merged this feature from the from Docking branch so it can be used earlier as as standalone feature) ...

- Added BeginTabBar(), EndTabBar(), BeginTabItem(), EndTabItem(), SetTabItemClosed() API.
- Added ImGuiTabBarFlags flags for BeginTabBar().
- Added ImGuiTabItemFlags flags for BeginTabItem().
- Style: Added ImGuiCol_Tab, ImGuiCol_TabHovered, ImGuiCol_TabActive, ImGuiCol_TabUnfocused, ImGuiCol_TabUnfocusedActive colors.
- Demo: Added Layout->Tabs demo code.
- Demo: Added "Documents" example app showcasing possible use for tabs.