In a grid I can change the page size to various values.
If I choose a page size that is larger than the total number of rows the paging control is removed from the grid and I no longer have an easy way to set the page size back.

The two attached screen shots show the page control for a grid that contains 60 rows.
With the page size set to the default value of 20 I can choose a different page size.
However once I choose a page size of 100 I can no longer reset the size back to 20 because the paging control has been removed.

The way I ran into it was:
I created a filter on a sample type that returned 60 samples.
I wanted to get a "big picture" view of the samples filtered so I changed the page size.
I then wanted to go back to a smaller view, but could not.
The only way I was able to do that was to remove the filter or leave the page and come back (which also removed the filter).

I'm not sure how common of a scenario this is, but it was a little annoying.
Using the UI Tenets & Traps this could be an "Inviting Dead End" or a "Irreversible Action".

If we do want to keep the page sizing control we would need to disable the "jump to" menu options (i.e. first & last). We already do that to some extent if you are on the first or last page.

Is this worth fixing?

Weird. I do agree it's an odd Irreversible Action, but OTOH there's no data lost or even out of view here...I guess we'd need to recalculate the pages on each page size change. So in your example we'd want to show:

"1 - 20 of 100" would say "1 - 100 of 100"
Previous/next buttons disabled (since already you're viewing all results)
"Jump to" options would be removed (since there's nothing to jump to)
Page size options (20, 40, etc.) would be unchanged so I could go back to 20 from 100.

It seems like a very minor thing but if it's easy to fix it'd definitely be nice to do. :-)

Thanks, Andrew for the proposal on expected / desired behavior. Adding dev estimate and passing to triage for milestone and priority assignment.

Seems reasonable to address but not particularly high priority

Fix has been merged to develop and will be in LK v22.7.

Validated.