Fixed unused argument warning when compiling with IM_ASERT() evaluating to an empty macro.

Version 1.68

Selectable: add support for specifying text alignment on selectables (#2347) ...

Adds a style variable to Selectable that allows clients to specify the
text alignment within Selectables, adds a section in the demo to
demonstrate selectable text alignment, and a pair of sliders in the
style editor to change selectable alignment on the fly.

In terms of implementation, this one is extremely simple: Selectable was
already calling an API that supports text alignment, but had hard-coded
it to top-left. This changes that to just pass the style variable
straight through to RenderTextClipped. Backwards-compatibility is
preserved by defaulting the text_align parameter to (0, 0), i.e.,
top-left.

This also fixes a bug with selectable text rendering that caused
right-aligned text in a selectable to be clipped incorrectly, because
the wrong clipping rectangle was being used.

Scrollbar: Fade out and disable interaction when too small, in order to facilitate using the resize grab on very small window, as well as reducing visual noise/overlap. (+1 squashed commits) ...

Internals: Added GetScrollbarID(). (#1185)

Shallow tweaks

Tabs: Fixed border (when enabled) so it is aligned correctly mid-pixel and appears as bright as other borders.

ListBox/InputTextMultiline: Better optimized when clipped / non-visible.

DragScalarN, SliderScalarN, InputScalarN: Removed unnecessary string id after the integer PushID() calls.

Minor tweaks to reduce false positive of PVS Studio static analyzer.

Menus: Tweaked horizontal overlap between parent and child menu (to help convey relative depth) from using style.ItemSpacing.x to style.ItemInnerSpacing.x, the later being expected to be smaller. (#1086)

Plot: Register an ID to take the click the same way as other framed widgets. Set HoveredId in the FramePadding zone (between inner_bb and frame_bb).

Internals: Selectable: Fixed rendering width miscalculation when starting pos is not line start pos, which would generally be unnoticeable. Could affect group lock X with a smaller SetCursorPos value but that's unlikely to be used.

Internals: Removed unnecessary code.

Tabs: Moved Tab List Popup to left-side to match docking button. Highlight selected tab. (#261, #351)

Tabs: Non-docking tab bars are storing names to allow tab list button + whole style scaling. Added ImGuiTabBarFlags_TabListPopupButton flag to show a popup button on manual tab bars. Locking FramePadding for the scope of a tab-bar to avoid sheering/clipping of tab item. Made scaling of tab ellipsis less awkward. (#261, #351)

RadioButton: Fixed label horizontal alignment to precisely match Checkbox(). + Internals: Checkbox, RadioButton: Single call to ItemSize() for flow layout purpose.

Internals: DragScalar, SliderScalar: Calling ItemSize before ItemAdd as with every other widgets so we can more easily rearrange the signature of ItemXXX functions (toward allowing non-rounded sizes for scaling and flow layout).

Internals: Minor changes to TreeNodeBehavior() and Selectable() for the benefit of fhe range_select branch. (#1861)

Internals: Track ActiveIdHasBeenPressed (similar to ActiveIdHasBeenEdited). This is currently mostly for the benefit of the range_select branch. (#1861)

Internals: InputScalarAsWidgetReplacement: Fixed seemingly unnecessary calling of SetActiveID/SetHoveredID every frame, which in turns allow us to remove the g.ActiveIdAllow/Block settings duplicated.

InputText: Fixed a bug where ESCAPE would be first captured by the Keyboard Navigation code. (#2321, #787)

InputText: Fixed a bug where ESCAPE would not restore the initial value in all situations. (#2321) [@relick]

imgui-test: Added extra item info callbacks. Using nav_bb for interactions when possible. Comments, Demo tweaks.

Persistently fixing some PVS-Studio static analyzer false positive warnings.

Using IM_UNUSED() macro.

Fix various XCode and PVS-Studio static analyzer warnings (#2309)

Fixed range-version of PushID() and GetID() not honoring the ### operator to restart from the seed value.

Removed trailing spaces (#2038, #2299)

Added checks for "zero-as-null-pointer-constant" warnings for older Clang (#2299, followup to #2277)

Various tweaks and fixes as suggested by PVS Studio (thanks PVS Studio!)