Examples: DirectX12: Various tidying up.

Examples: OpenGL3: Minor tweaks, clarifications + not calling glBindBuffer more than necessary in the render loop.

Docking: Fixed focus restore lagging by a frame when a tab stops being submitted. (#2109) Building on a little build of technical debt there, should transition toward a more general docking-agnostic system (#2304)

Viewport: Renamed member + added note about a Docking issue with restoring focus.

Docking: Remove code in BeginDocked() to set HiddenFramesCannotSkipItems based on upcoming tab bar selection, solely based on focus (might break something subtle?). Follow-up to c355ed1. (#2453, #2109)

Docking: Disable SkipItems when directly/programmatically focused (possible generalization of code currently in BeginDocked which relies on tab bar interaction, will remove that code in next commit). (#2453, #2109)

Merge branch 'master' into docking ...

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

Internals: Renamed the ImGuiWindow HiddenFrameXXX fields to decorrelate them from resizing behavior, as those values are set by other logic.

Docking: Added ImGuiDockNodeFlags_NoTabBar (not exposed publicly). (#2423, #2109)

Docking: Internals: Moved CentralNode and HiddenTabBar state into LocalFlags for consistency. (#2423, #2109)

Docking: Separating SharedFlags vs LocalFlags in dock node so settings can be applied to individual nodes. Made _NoResize logic on single node applies as expected. (#2423, #2109)

Docking: Fix DockBuilderAddNode() not storing flags when creating floating node.

Renamed ImGuiDockNodeFlags_Dockspace to ImGuiDockNodeFlags_DockSpace for consistency. DockBuilderCopyDockspace() to DockBuilderCopyDockSpace(). Made casing consistent elsewhere. (#2109)

Docking: Renamed ImGuiDockNodeFlags_PassthruDockspace to ImGuiDockNodeFlags_PassthruCentralNode. + Comments, shallow tweaks. (#2109)

Docking: Tweak and silencing PVS studio static analyzer (back to zero warnings among our selected ones).

Docking: Fixed an issue where windows docked into a node that's part of their dockspace wouldn't recover their order correctly after init. (#2109) ...

(It only worked on floating dock node for the accidental reason that BeginDocked would generally early out on the first frame)

Docking: Wrapping tab bar creation/destroy to make it easier to debug them.

Docking: Fixed crash with ImGuiDockNodeFlags_AutoHideTabBar flag. (#2423, #2109)

Comments (#2441) + Freeglut fixes (#2430)

Rearrange code in UpdateMouseWheel(). (#2424, #1463) + Fix old io.FontAllowUserScaling feature (probably should be made obsolete, but until then best fixed)

Implement horizontal scrolling with Shift+Scroll ...

This is standard scrolling behaviour in most applications.

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui_internal.h

InputText: Fixed selection background starts rendering one frame after the cursor movement when first transitioning from no-selection to has-selection. (Bug in 1.69) (#2436) [@Nazg-Gul]

InputText: Simplify read-only code path.

IsWindowHovered() made change which should have no effect in master but fix result of IsWindowHovered(ImGuiHoveredFlags_ChildWindows) over multiple viewport in docking branch. (#2432)

Mention Julia binding in README (#2446) ...

Thank you!

Docking: BeginDocked() doesn't need to rely on tab bar data (will allow removing tab bar).

Docking: Preserve existing docked nodes when setting the ImGuiDockNodeFlags_NoDockingInCentralNode flag. (#2423, #2109)

Comments, todo list, remove trailing spaces.

Viewports: Fixed being unable to refocus windows when ConfigViewportsNoTaskBarIcon + ConfigViewportsNoDecoration are enabled. (#2420, #1542) [@PathogenDavid] + comments.