Fixed a PVS Studio static analyzer warning.

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	imgui.cpp

Internal: Extracted some of the Begin code into RenderWindowDecorations().

Internal: Extracted some of the Begin code into RenderWindowTitleBarContents().

Internal: Begin: Update rectangles before Scrollbar() which now uses them. Fixes 39eeda0.

Internals: Columns: Renamed fields. Comments and tweak. Moved a demo block.

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)

Viewports: Minor tweaks. (#2471)

Viewports: Fix to avoid SetNextWindowViewport being overrided by creation of a standalone viewport. (#2544, #1542)

Version 1.71 WIP + fixed minor typo

Version 1.70

Merge branch 'master' into docking ...

# Conflicts:
#	examples/README.txt
#	examples/imgui_impl_dx9.cpp
#	imgui.cpp
#	imgui.h

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.

Internals: Fixed incorrect repeat delay/rate calculation in IsMouseClicked() with repeat flag leading to involontary but thankfully doubling the rate. Using our standard function, making the multiplicator explicit.

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)

Internals: Rename GetContentRegionMaxScreen() -> GetWorkRectMax(). At this point this is mostly useful to facilitate merge of other branches.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_vulkan.cpp
#	imgui.cpp

Internals: SettingsHandlerWindow_ReadLine uses context parameter.

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)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

Amend 48a09a7 with changelog, breaking changes, tweak demo code for spacing. (#2518)

Tidying up BeginMenu() code + comments.

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.

Fix 61d9258 when there is not scrollbar "Window: Fixed contents region being off by WindowBorderSize amount on the right when scrollbar is active."

Internals: Renaming. Renamed ImGuiPopupRef to ImGuiPopupData for consistency and added constructor.