Request: Remember stroke-width and style selector units per document

Migrated from: https://bugs.launchpad.net/inkscape/+bug/636626 and split from #2432 as identified by @jhofinger in #2432 (comment 327010566)

Summary:

• When I assign stroke widths in points in a drawing that has e.g. inches as document units, the next time I open the drawing the stroke width units revert back to inches. It's a small annoyance, but after the nth time reverting the same thing it becomes wearing.

Steps to reproduce:

• open Inkscape (defaults to mm units)
• Draw a path
• Open Fill and Strokes Dialog
• Change Stroke width units to cm
• Save, restart, and reopen

What happened?

• Units aren't remembered, but take on the document display units instead

What should have happened?

• Have more fine grained control/memory of the units. At least for the style selector in the bottom left, and the stroke width for the fill and stroke dialog.
• I don't think it needs to be very complex, if the display units are changed, all units should be synced to it (unless it has an exception, e.g. text toolbar units).
• Maybe the document properties dialog could show an indicator when all units are not synced?

Related reports (identified by su_v)

Bug #568196 “inconsistent display units” (summary: expects the toolbars to share the same units) Bug #362995 “Default Units in Document Properties ignored” (tracked in inkscape#208 and related issues) Bug #299207 “Working with native units” (fix released, but see original issue. Full support of native units is a can of worms) Bug #171608 “Add a GUI to configure default units for all documents” (I guess resolved?) Bug #166335 “Unit type not saved in "Stroke width"” (resolved)

Version Info:

Inkscape 1.1-dev (d3f8295e8e, 2020-07-27) Linux Mint 20