Window rectangles: Changed WorkRect to cover the whole region including scrolling (toward obsolete ContentsRegionRect) + using full WindowPadding*1 padding. ...

Tweaked InnerClipRect.
TreeNode, CollapsingHeader: Fixed highlight frame not covering horizontal area fully when using horizontal scrolling. (#2211, #2579)
TabBar: Fixed BeginTabBar() within a window with horizontal scrolling from creating a feedback loop with the horizontal contents size.
Columns: Fixed Columns() within a window with horizontal scrolling from not covering the full horizontal area (previously only worked with an explicit contents size). (#125)
Demo: Added demo code to test contentsrect/workrect

Clarified behavior of SetNextWindowContentSize(). Content size is defined as the size available after removal of WindowPadding on each sides. So SetNextWindowContentSize(ImVec2(100,100)) + auto-resize will always allow submitting a 100x100 item without creating a scrollbar, regarding of WindowPadding.The exact meaning of ContentSize for decorated windows was previously ill-defined.

Comments about obsoleted features version. Todo. Clarify tab bar initial offset (useful if we decide to remove the half-windowpadding clip margin).

Nav: Fixed rare crash when e.g. releasing Alt-key while focusing a window with a menu at the same frame as clearing the focus. This was in most noticeable in some back-ends with emits key release events when focusing another viewport. (#2609)

Combo: Fixed rounding not applying with the ImGuiComboFlags_NoArrowButton flag. (#2606, #2607)

Nav: Fixed gamepad/keyboard moving of window affecting contents size incorrectly, sometimes leading to scrollbars appearing during the movement. + minor fix with the mostly dead Ctrl+wheel scaling.

Examples/Backends: Metal: Added support for large meshes (64k+ vertices) with 16-bits indices, enable 'ImGuiBackendFlags_HasVtxOffset' config flag in back-end. (#2591, #2592)

Renamed ImGuiBackendFlags_HasVtxOffset to ImGuiBackendFlags_RendererHasVtxOffset to match naming convention already used in viewport/docking branch. (#2591) + Fix OpenGL3 code missing flag.

Examples/Backends: DirectX9/10/11/12, Vulkan, OpenGL3 (Desktop GL only): Added support for large meshes (64k+ vertices) with 16-bits indices, enable 'ImGuiBackendFlags_HasVtxOffset' config flag in back-end. (#2591)

ImDrawList: Added ImDrawCmd::VtxOffset value to support large meshes (64k+ vertices) using 16-bits indices. To enable the feature, the renderer back-end needs to set 'io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset' and honor the ImDrawCmd::VtxOffset field. Otherwise the value will always be zero. This has the advantage of preserving smaller index buffers and allowing to execute on hardware that do not support 32-bits indices. ...

ImDrawList: Added ImDrawCmd::IdxOffset value, equivalent to summing element count for each draw command. This is provided for convenience and consistency with VtxOffset. (#2591)

CollapsingHeader: When a close button is enabled, better clip the label to avoid overlap. (#600)

Changelog, minor tweaks. (#2585)

Added full "Dear ImGui" prefix to the title of "Dear ImGui Demo" and "Dear ImGui Metrics" windows. Shortened amount of nodes in columns>tree demo.

Comments, todo entries, moved ImGuiSelectableFlagsPrivate in higher ranges to match others.

ColorEdit: Fixed the color picker popup only displaying inputs as HSV instead of showing multiple options. (#2587, broken in 1.69 by #2384).

Style: Added style.WindowMenuButtonPosition (left/right, defaults to ImGuiDir_Left) to move the collapsing/docking button to the other side of the title bar.

Internal: CloseButton takes an upper-left corner + a size to be consistent with similar widgets.

Fixed InputScalar, InputScalarN, SliderScalarN, DragScalarN with non-visible label from inserting style.ItemInnerSpacing.x worth of trailing spacing.

ImFontGlyphRangesBuilder: Fixed unnecessarily over-sized buffer, which incidentally was also not fully cleared. Fixed edge case overflow when adding character 0xFFFF. (#2568)

Fixed crash when appending with BeginMainMenuBar() more than once and no other window are showing. (#2567) + comments

Update changelog, comments, made empty/no-text clipboard return NULL as with other implementation. Minor style tweaks. (#2546) ...

Fixed IMGUI_DISABLE_WIN32_FUNCTIONS not disabling IME code.

Fixed uses of IsItemDeactivated(), IsItemDeactivatedAfterEdit() on multi-components widgets and after EndGroup(). (#2550, #1875)

Fixed InputFloatX, SliderFloatX, DragFloatX functions erroneously reporting IsItemEdited() multiple times when the text input doesn't match the formatted output value (e.g. input "1" shows "1.000"). It wasn't much of a problem because we typically use the return value instead of IsItemEdited() here. (#1875, #2034)

Internal: Renamed fields + minor tweaks (probably shallow break stack-layout pr, sorry!)

Renamed SetNextTreeNodeOpen() to SetNextItemOpen(). Refactored SetNextItemXXX stuff to match SetNextWindowXXX code closely.

FreeType: Added RasterizerFlags::Monochrome flag to disable font anti-aliasing. (#2545) Combine with RasterizerFlags::MonoHinting for best results.

IO: changed AddInputCharacter(unsigned short c) signature to AddInputCharacter(unsigned int c). ...

Examples/Backends: Don't filter characters under 0x10000 before calling io.AddInputCharacter(), the filtering is done in io.AddInputCharacter() itself. This is in prevision for fuller Unicode support. (#2538, #2541)

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