Actually there is a way how to have big icons: you have to
disable Window Buttons/Properties/Show button labels
and 2) have "Panel Preferences/Appearance/Icons/Adjust size automatically" off
and 3) have "Panel Preferences/Appearance/Fixed icon size" at least 32
Then there are 32 pixel icons instead of 16 pixel ones (they are somewhat misplaced to the right on the buttons by one or two pixels, though).
But I would like to have big icons with labels, and the best would be if they scaled with the size of the panel.
Patch to use big icons. Increase the size of panel to at least 36 pixels to see the change. This of course does not create scalable icons, but more or less achieves what I wanted.
Patch 9082, "Big icons in window buttons": bigicons.patch
The patch has the following problem: If the panel size is 50 pixels, the window buttons become twoline, individual buttons are 25 pixels high, yet the icons are still 32pixel big, i.e. too big for the buttons.
I want to subscribe to this bug.
For a netbook screen at least, the new gtk3 look of window buttons in xfce 4.14 show too small icons. The "button" itself is ok, but it has a lot of "border" or background (usless, why?) and the icon itself looks too small inside.
Though not ideal, the thing was better in xfce 4.12. Why this regression?