Added GetGlyphRangesVietnamese() helper. (#2403)

Internal: Removed unused fields from ImGuiMenuColumns.

Docking: Fixed node merging altering window position incorrectly in a way that would make SizeContents incorrect for the next frame (making scrollbar flicker). (#2414, #2109)

Viewport: Popups and Tooltips viewports are correctly parented to the parent window's viewport. (#2409, #1542)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp
#	imgui.cpp

Examples: Win32+DirectX: moved helper functions below main.

Viewports: Fixed delayed window pos->viewport pos sync leading to monitor not being updated at the time of clamping window position in Begin. (#2415, #1542)

Viewports: Renamed ConfigViewportsNoParent to ConfigViewportsNoDefaultParent. Fix outdated comments in examples.

Docking: Fixed an issue where removing the last window from a dockspace node that is not a central node without remove the node. (#2414, #2109)

Fix typos. (#2413)

Don't use const qualified parameters in declarations. ...

This fixes warnings from clang-tidy like this:

    parameter 'v_max' is const-qualified in the function declaration;
    const-qualification of parameters only has an effect in function definitions

Since values (rather than references or pointers) don't need to be
const, they don't need to be marked that way in the function declaration.

Added ImGuiColorEditFlagsFlags_InputHSV. (#2383, #2384)

ColorEdit: Fixed tooltip not honoring the ImGuiColorEditFlags_NoAlpha contract of never reading the 4th float in the array (value was read and discarded). (#2384)

Moved placeholder sections to match Docking branch. Comments.

Fix typos. (#2411)

Merge branch 'master' into docking

Refactor: Move viewport code under other subsystem to simplify merging (4) (moving in multiple commits to make diff/patch behave nicely)

Refactor: Move viewport code under other subsystem to simplify merging (3) (moving in multiple commits to make diff/patch behave nicely)

Refactor: Move viewport code under other subsystem to simplify merging (2) (moving in multiple commits to make diff/patch behave nicely)

Refactor: Move viewport code under other subsystem to simplify merging (1) (moving in multiple commits to make diff/patch behave nicely)

Internal: Columns: Allow to use BeginColumns(1) so code designed for variable number of columns can still call NextColumn etc. (#125)

TabBar: Fixed ImGuiTabItemFlags_SetSelected being ignored if the tab is not visible (with scrolling policy enabled) or if is currently appearing.

Made ImS8 and ImS16 explicitly signed in case some crazy SDK decide to flip the signedness over. (#2408)

Fix for Android char being unsigned by default (#2408)

Examples: DirectX9: Added support for multi-viewport (#2394)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui_demo.cpp

Internals: ColorEdit: Minor optimizations. Initialize internal arrays as static const, avoid unnecessary HSV->RGB conversion.

Demo: Renamed ShowHelpMarker() -> HelpMarker(). Fixed minor PVS warning. Removed unnecessary casts.

Examples: DirectX9: Minor changes to match the other DirectX examples more closely. (#2394)

InputTextWithHint: Fix for Password fields. Update changelog, demo. (#2400)