Can't use start menu search

[Quboid]

For the past week or so I have been unable to use the start menu "Search for apps, settings, and documents" search bar; the way I have mostly used to launch programs for years. I can not select the box: if I click on the text box it does not receive focus; if I type nothing is entered in that box; if I try to tab to give the box focus it never does. The mouse pointer does switch to the text caret when hovering over the text box as expected.

 

I did install a couple of Windows updates on the 15th, which may be when this started: KB5028851 and KB5028185.