until 18.04
- Open / Create ~/.gtkrc-2.0
- Here you can set all kinds of specific styles
Insert the following code:
style "window-buttons"
{
font_name = "Arial 17"
XfceTasklist::max-button-size = 32
}
restart your panel: xfce4-panel -r
explanation
- style
Window-Buttons
is used by the widget(?) "Window-Buttons", which is the name for the tasklist. I found this information here
XfceTasklist::max-button-size = 32
changes the button size (if you miss that, text will be cropped on the top and bottom. Information here
- If you want to change all sizes instead, see this link
- General rc-file information is here
from 18.10
You need to use gtk3. I couldn't get it to work here, but apparently you use the file ~/.config/gtk-3.0/gtk.css
Here is an information page (that doesen't work for me right now)