Bizarre display effects in panx

i frequently do a formulafill, for example, and nothing happens on screen.
the data is there but you can’t see it; the cells still look empty.
if you completely cause the screen to refersh, say selectreverse and selectreverse again, you can see that the formulafill did, in fact, execute.
took me a while to catch on to this.

also, today, i just closed a file, and it’s still on screen.
i can click the window, and panx becomes the active app.
then i can do cmd-w, sh-cmd-w and nothing happens.
in fact, those menu items are grayed out.
i can look at the window menu and the filename isnt there.
but the window is onscreen.

this is on quite an old mac: macpro5,1, quad-core intel xeon 2.8 ghz, 5 gb ram.
it does kind of run os 10.12.1.
i say ‘kind of’ because i get way more spinnies than anyone should have to see.
it ran beautifully on 10.6. i upgraded just for panx.
is my machine just too old for panx?

i’d also like to add that panx seems to display numbers in an unexpected manner.
in a table with several fields, datatype float, no output pattern specified, panx displays numbers with decimals as you would expect, but if the number happens to be an integer, it displays the number followed by .00.