setWindowFlags(Qt::ToolTip) freezes Gnome

Since vlc 3.0.3, when hoovering the mouse over the sliding time bar when a media is playing and the vlc window is not on top, gnome freezes.
Everything freezes and no input is allowed.The only way to unfreeze is to force reset the machine (and lose everything)

I have traced back the offending vlc commit to https://git.videolan.org/?p=vlc.git;a=commitdiff;h=58155349a053d38d882d47357b225b8703c696ac
Qt code displays the problem too. See the attachment.

References:

https://bugzilla.gnome.org/show_bug.cgi?id=777289

https://trac.videolan.org/vlc/ticket/20763

https://bugzilla.rpmfusion.org/show_bug.cgi?id=4596