Internals: Checkbox: Added undocumented mixed/indeterminate/tristate support via ImGuiItemFlags_MixedValue. (#2644)

Style: Attenuated default opacity of ImGuiCol_Separator in Classic and Light styles.

ImDrawListSplitter: Fixed memory leak when using low-level split api (was not affecting ImDrawList api, also this type was added in 1.71 and not advertised as a public-facing feature).

Word-wrapping: Fixed overzealous word-wrapping when glyph edge lands exactly on the limit. Because of this, auto-fitting exactly unwrapped text would make it wrap. (fixes initial 1.15 commit, 78645a7d).

Examples: SDL+DX11: Changelog, readme, batch files, fixed vcxproj, minor stylistic fixes + minor sync of other main.cpp files. (#2632)

Window: Fixed InnerClipRect right-most coordinates using wrong padding setting (introduced in 1.71).

Updated Ogre bindings (#2619) ...

And support python

ImDrawList: Fixed CloneOutput() helper crashing. Also removed unnecessary risk from ImDrawList::Clear(), draw lists are being clear before use each frame anyway. (#1860)

ImDrawList::ChannelsSplit(), ImDrawListSlitter: Fixed an issue with merging draw commands between channels 0 and 1. (#2624) Introduced by cef88f6.

Removed redirecting functions/enums that were obsoleted in version 1.51 (June 2017): ImGuiCol_Column*, ImGuiSetCond_*, IsItemHoveredRect(), IsPosHoveringAnyWindow(), IsMouseHoveringAnyWindow(), IsMouseHoveringWindow(), IMGUI_ONCE_UPON_A_FRAME.

Version 1.72 WIP

Version 1.71 + comments

Readme, comments, dear imgui prefixes

Log/Capture: Fixed BeginTabItem() label not being included in a text log/capture. ...

Extracted tab rendering code into a RenderTextEllipsis() function.

Window: child windows outer decorations (e.g. scrollbar) are rendered as part of their parent window, avoiding the creation of an extraneous draw command. ...

+ Metrics: inverted color of clip rect vs vertices bounding box when hovering a draw command, so the color matches the per-vertex preview.

Synced/merged minor cruft from docking branch to minimize drift. AFAIK the only meaningful no-op change is that the call UpdateHoveredWindowAndCaptureFlags() was moved above UpdateMouseMovingNewFrame() to match what docking branch has been doing for a while.

ImDrawCallback: Allow to override the signature of ImDrawCallback by #define-ing it. This is meant to facilitate custom rendering back-ends passing local render-specific data to the draw callback.

Revert "Changed syntax for (very rarely used) IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT mechanism, instead you only need to '#define ImDrawVert MyDrawVert' to use this feature, avoiding the need to declare the entire structure within an awkward macro. Using the old macro will now error with a message pointing you to the new method. (#38, #103, #1172, #1231, #2489)" ...

This reverts commit 597c024.

Changed syntax for (very rarely used) IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT mechanism, instead you only need to '#define ImDrawVert MyDrawVert' to use this feature, avoiding the need to declare the entire structure within an awkward macro. Using the old macro will now error with a message pointing you to the new method. (#38, #103, #1172, #1231, #2489)

Window: Fixed one case where auto-resize by double-clicking the resize grip would make either scrollbar appear for a single frame after the resize. Moved Scrollbar visibility block.

Scrollbar overlap an extra WindowBorderSize amount on the left to make all distances consistent. Reverted to BorderSize not affecting work/contents rectangles. Scrollbar, Style: Changed default style.ScrollbarSize from 16 to 14.

Fixed newly created window (e.g. appearing child window) from having scrollbar active on the first frame. (fix 6e03b27) + reworded code a little. (+1 squashed commits) ...

Fixed auto-resize with AlwaysVerticalScrollbar or AlwaysHorizontalScrollbar flags not taking account of the expect scrollbar sizes.

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.