Save and Save as choosing existing file to overwrite hangs all, confirmation question "File exists, would you overwrite it?" shown only half - empty title bar and white blank window

all stopped, Wait, working mouse pointer rotates to the infinite. No remedy, only terminal with
killall -9 heekscad
with loosing of all work :(
Not every time, 3 times in a row, now I recheck it and I was able to save the file. (These are the worst, mistakes that occur only occasionally)
HeeksCAD 1.4.0
Ubuntu 18.04 64bit updated daily
Save and Save as choosing existing file to overwrite hangs all, confirmation question "File exists, would you overwrite it?" shown only half - empty title bar and white blank window

all stopped, Wait, working mouse pointer rotates to the infinite. No remedy, only terminal with
with loosing of all work :(
Not every time, 3 times in a row, now I recheck it and I was able to save the file. (These are the worst, mistakes that occur only occasionally)
HeeksCAD 1.4.0
Ubuntu 18.04 64bit updated daily