Version 1.71 WIP + fixed minor typo

Version 1.70

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.

Tidying up BeginMenu() code + comments.

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.

Internals: Added DataTypeApplyOp, DataTypeApplyOpFromText to imgui_internal.h

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

Internals: Exposed ImGuiDataTypeInfo, DataTypeGetInfo(), DataTypeFormatString(). Comments.

Separator: Declare its thickness (1.0f) to the layout, making items around separator more symmetrical.

Nav: Fixed Drag/Slider functions going into text input mode when keyboard CTRL is held while pressing NavActivate.

Internals: TempInputText: Tidying up DragScalar / SliderScalar / TempInputTextScalar.

Internals: TempInputText: Rename InputScalarAsWidgetReplacement() -> TempInputTextScalar(), ScalarAsInputTextId -> TempInputTextId, small tidying up in affected functions.

Internals: Using more explicit PushOverrideID() helper + renamed equivalent internal tree helper.

MenuItem, BeginMenu: Fix undesirable tall frames in horizontal layout context, which would be visible when trying to use rounded selectable/menus. ...

PushStyleVar: Added comments in the assert message.
Minor tweaks.

Misc comments, internal renaming, added disable indentation option to Columns demo section.

Internals: ImHashStr() default parameter.

Added SetNextItemWidth() helper to avoid using PushItemWidth/PopItemWidth() for single items.

Added commentary about ContentRegion functions. Added internal GetContentRegionMaxScreen() to facilitate internal code at the moment.

Internals: Moved CalcItemSize next to CalcItemWidth, added comments to clarify their respective intent. Should have no side effect.

Combo, Slider: Improve rendering in situation when there's there's very little space available.

Internals: Columns: Tweaks, renaming. Metrics: Show rectangles for child windows. ...

Renamed SameLine() first parameter.

Metrics: Added "Show windows rectangles" tool to visualize the different rectangles.

Internals: Columns: Some renaming, extracted code into GetColumnsID().

Tests: Added hook/tweaks for imgui-test engine. + Fixed warnings.

PlotLines, PlotHistogram: Ignore NaN values when calculating min/max bounds. (#2485)

Internals, Docs: Added a bunch of clarification about ButtonBehavior in the form of a table (and to facilitate writing tests)

Internals: Merge minor things from range_select branch. Added ImGuiButtonFlags_NoHoveredOnNav. Added IsItemToggledSelected() - unused here. Renaming.

Internals: Selectable: Added ImGuiSelectableFlags_AllowItemOverlap in imgui_internal.h (~ #684, #2341)

Internals: Tweak ItemSize calls. Added todo items.