Minor tweaks/comments. Note that the reordering the one subtraction caused subtle havoc before the patch in 9ac8820.

Fixed non-pixel aligned bounding box of window resize grip, / which triumphally led to any re-arrangement of operations inside the resize grip code outputting non-exact size_target values which led to unstable window position because clamping code uses size in a subtraction, etc etc. Lovely how a whole system can be made to act weird with a single bad input.

Child window with MenuBar use regular WindowPadding.y so layout look consistent in child or in a regular window.

ButtonBehavior: Fixed ImGuiButtonFlags_NoHoldingActiveID from incorrectly setting ActiveIdClickOffset, which probably have no known effect, but it is more correct this way. (#1418)

LowerBound() minor tweaks

Internal: FindWindowByName() faster and doesn't touch every windows

Fixed auto-resize allocating too much space for scrollbar when SizeContents is bigger than maximum window size (fixes c0547d3) (#1417)

Begin: Simplified code and fixed a bug where appending into a window a second time (from a remote window) would incorrectly overwrite RootWindow with the current window in the stack. Our docking code uses this pattern.

RenderTriangle() minor tweak to align Left/Right and Up/Down arrow extents visually

IsWindowHovered() returns true when moving window (#1382, #1404)

IsWindowHovered(): Added ImGuiHoveredFlags_FlattenChilds flag. Made IsRootWindowOrAnyChildHovered() obsolete in favor of IsWindowHovered( ImGuiHoveredFlags_FlattenChilds) (#1382, #1404)

IsWindowHovered() Fix behavior when an item is active to use the same logic as IsItemHovered() (#1382, #1404)

Minor tweaks to the user guide.

Merge pull request #1402 from elect86/patch-1 ...

Minor fix typo

Added assertions and comments for incorrect use/understanding of IsWindowFocused() etc. functions

Update imgui.cpp

Maintaining ActiveIdTimer and HoveredIdTimer (the later is useful for drag and drop, both will be of course for creators of custom widgets)

ColorTooltip: Resize ColorButton to align better with text, now that ColorButton provides a text baseline (0260fdd)

Styles: Moved Classic colors code to imgui_draw.cpp. Sneakily added a StyleColorsDark() function.

Version 1.53 WIP

IO: Tracking extra mouse dragging data which is convenient for implementating various manual drag and drop patterns.

Version 1.52

Begin: Fix for unused "Debug" (fix for 3b83cd2 )

Begin: Moved some code inside of the big if (first_begin_of_the_frame) scope

NewFrame: Allow MovedWindow setting the ImGuiWindowFlags_NoInputs after moving has started in order to be able to detect windows below it, which is useful for e.g. docking mechanisms.

NewFrame: Removed unnecessary call to FindHoveredWindow() and simplified code (went through this multiple times, hopefully haven't broken anything)

Internal: BeginTooltipEx() in imgui_internal.h

Merged a bit of code from Navigation branch to ease further merging (InnerRect is currently not required in the Master branch)

Minor renaming.

Comments about mouse setup and clearing HoveredWindow when mouse down isn't owned by imgui (will affect some future hovered test and drag'n drop patterns) (#143, #1382, #1392)