ImDrawData: Added FramebufferScale field (currently a copy of the value from io.DisplayFramebufferScale). ...

This is to allow render functions being written without pulling any data from ImGuiIO, allowing incoming multi-viewport feature to behave on Retina display and with multiple displays. If you are not using a custom binding, please update your render function code ahead of time, and use draw_data->FramebufferScale instead of io.DisplayFramebufferScale. (#2306, #1676)
Examples: Metal, OpenGL2, OpenGL3: Fixed offsetting of clipping rectangle with ImDrawData::DisplayPos != (0,0) when the display frame-buffer scale scale is not (1,1). While this doesn't make a difference when using master branch, this is effectively fixing support for multi-viewport with Mac Retina Displays on those examples. (#2306) Also using ImDrawData::FramebufferScale instead of io.DisplayFramebufferScale.
Examples: Clarified the use the ImDrawData::DisplayPos to offset clipping rectangles.

Window: Fixed initial width of collapsed windows not taking account of contents width (broken in 1.67). (#2336, #176)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_demo.cpp

Minor tweaks to reduce false positive of PVS Studio static analyzer.

Menus: Tweaked horizontal overlap between parent and child menu (to help convey relative depth) from using style.ItemSpacing.x to style.ItemInnerSpacing.x, the later being expected to be smaller. (#1086)

Added IsItemActivated() as an extension to the IsItemDeactivated/IsItemDeactivatedAfterEdit functions which are useful to implement variety of undo patterns. (#820, #956, #1875)

Internals: EndGroup: Removed unnecesary parameter to ItemSize()

Internals: Removed unnecessary code.

Merge branch 'master' into docking ...

# Conflicts:
#	imgui_internal.h
#	imgui_widgets.cpp

Fonts: Fixed crash if FontGlobalScale is zero. Correctly debug naming default font if not 13 px. Demo: Moved PopupRounding along with other rounding values. Metrics: Displaying indexes with idx to be correct / less misleading.

Docking: Fixed less of node size/pos caused by 1f2bdd37 (#2109)

Docking: Fixed dragging docked window with _NoMove flag (#2325)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui.h

Internals: Exposed internal SetWindowPos to imgui_internal.h (for imgui-test)

Revert part of change from 5536eded. Fixed drag and drop in docking branch. (#2331, reopening #2325)

Removed io.DisplayVisibleMin/DisplayVisibleMax (which were marked obsolete and removed from viewport/docking branch already).

Removed io.DisplayVisibleMin/DisplayVisibleMax (which were marked obsolete and removed from viewport/docking branch already).

Merge branch 'master' into docking (enable range_select merge) ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

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)

Docking: Extracted code into a DocknodeUpdateTabListMenu() functions + minor other changes.

Comments. Fix duplicate entries in About box. Synchronize a few small changes from Master branch.

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

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp

Docking: Builder: Added DockBuilderSetNodePos, DockBuilderSetNodeSize, allow DockBuilderAddNode creating floating node (dockspace requires ImGuiDockNodeFlags_Dockspace) (#2109)

Docking: VisibleWindow of a node spread its _NoMove attribute to the node (fixed dragging or undocking of dock node host from collapse button). (#2325, #2109)

Docking: Fixed faulty undocking of windows with the _NoMove flag. (#2325, #2109) ...

Whereas BeginAsDockableDragDropTarget could be reworked to filter, we simply set g.HoveredWindowUnderMovingWindow to be NULL when MovingWindow is not set, which was the initial intent.
Also fixed some comments and removed unused braces in TabItemEx().

Docking: Removed unnecessary ImGuiTabItemFlags_DockedWindow internal flag.

Viewport: Added ImGuiViewportFlags_NoFocusOnClick + support in imgui_impl_win32. Made windows with no decoration always set the _NoFocus flags. (#1542, #2117) ...

Fix e.g. clicking on protruding combo box stealing highlight from parent window with decoration.

Viewport: Popups by default merge into parent/host viewport as they have no decoration (same as menu/child). (#1542)