Show number of items selected in action bar in a list selection

Your idea

When a list of items is selected, there should be an indication in the action bar on how many items are in the list. Just simply displaying "List selection" is not very useful.

Problem to be solved

Displaying a number is useful for:

• Checking if there are more or less items than expected in a score using filtered selection
• Signaling if something is still selected before deleting/editing multiple items of a known count

These are, admittedly, very niche uses, but I have found myself in need of them occasionally.

Prior art

No response

Additional context

What is displayed currently:

What could be displayed:

Checklist

• This request follows the guidelines for reporting issues
• I have verified that this feature request has not been logged before, by searching the issue tracker for similar requests

The issue describes the desktop list-selection action bar but names no source files, tests, or entry points. Start by locating the code that renders the current “List selection” label and the list-selection state, then verify that the action bar shows the selected-item count and that the existing selection actions still work.