QPushButton, On :hover the text-decoration: underline. Underline is obfuscated by all non-transparent background colors.

The text-decoration:underline on QPushButton seems to be obfuscated by any background color. It works fine if the background is transparent.

For example, this works:

#printBtn:hover { background-color: transparent; text-decoration: underline; }

This does not work:

#printBtn:hover {  text-decoration: underline; }

I originally brought this up on Stack Exchange here.

Another user S.Monteleone offered this fix/advice to me.:

It is indeed a Qt bug, I was able to obtain the same result with Qt 5.10.1.

QPushButton does support font changes. That was not the case before, but it has been "fixed" (see "QPushButton: draw label using the stylesheet's font." b3c5d3dde9d554dcae0888e3fb4e583919cd102a  this commit).

I guess the issue is at line 3484 of file qtbase/src/widgets/styles/qstylesheetstyle.cpp:

if (rule.hasPosition() && rule.position()->textAlignment != 0) {

because the else part of this if clause (line 3556) will call:

ParentStyle::drawControl(ce, &butOpt, p, w);

In fact, you can force it to work also by setting the text-align:

#printBtn:hover {  text-align: center; text-decoration: underline; }

I'm afraid there's not much we can do except filing a bug report at http://bugreports.qt.io.