Regression-test: wiggling the mouse-cursor over text nearby checkbox/radio-buttons makes their text flicker

r74608 affected
0.4.5  affected
r73913 affected
r73907 affected
r73890 flickers, but to a smaller degree
r73881 flickers, but to a smaller degree
r73879 flickers, but to a smaller degree
r73877 flickers, but to a smaller degree
r73806 flickers, but to a smaller degree
r73805 ok
r73795 ok
r73700 ok
r73557 ok
r68903 ok