With Xfce Panel 4.12.2 and GTK+ 3.22.26 I am unable to enter a number directly in the field *Number of workspaces*. Only the arrow buttons can be used to change the value.
Same with 4.13.2git-c3d6b3b5, although the workspace settings dialog is part of xfwm.
Assigning to the correct product. Funny, now I can change the workspace number with keyboard, maybe xfwm4 is still gtk2-based on my work's pc, here I'm running xfwm4 from git (b2ca8f72).
it works in git master with gtk3, I don't think it's worth fixing in 4.12