Dell Venue 8 Pro with Windows 10, suddenly no onscreen keyboard in tablet mode

Yesterday it worked.  --Though I worry I'm headed down a bad road since in the last month, I've started having to hold the start/stop button down about 5 seconds in order to turn it on.   I upgraded from Windows 8 to Windows 10 on this tablet over 6 months ago, in August, 2015.

This new problem is that when I'm in tablet mode and use a non-tablet app like the Chrome browser, the onscreen keyboard fails to materialize when I tap an input area.  The same thing happens when I use another Windows program that is a card file.  But it doesn't happen, that is the onscreen keyboard does come up even in tablet mode, when I use Office programs like Word or Excel, or Microsoft Edge browser instead of Chrome.  

 If I manually switch to non-tablet mode, the onscreen keyboard doesn't come up when I tap an input area either, but at least I've set it up so that the keyboard icon displays in the task bar in non-tablet mode.  So I can select the keyboard from there and then I can enter data in the browser's search field.  

This used to work, up until yesterday, so that without having to manually switch out of table mode, I could select the Google browser app from START screen, it would pop open to the desktop screen, and when I tapped an input area like Search,  the onscreen keyboard would come up automatically.