Plain and simple, zooming or panning in 2019 CorelDraw leads to portions of the displayed object area to be blanked out. Zooming out and back restores this obvious display buffering failure... but as soon as the zoom in is done again, or a pan is done, then blank out..
ctrl w. Just because it was noticed doe not mean it got fixed.
Then there's that!
I, too, have run into this problem on occasion. Whenever I run into any type of display problem switching to wire frame view and back to enhanced view seems to fix the problem at the moment though not solve the cause.
The cause is the program coding. No patch, no change it's that simple.
Same thing here. Pick tool can't select sometimes during these white outs.