I am running Lubuntu 12.04 and have installed Dolphin, VLC and Skype. I adjusted fonts for the menu of the programs to Droid Sans 8, but Dolphin, VLC and Skype do not accept this setting and they look different. How can I set the font on these programs?
It happens because those programs do not use GTK+. When someone say that a program is native it means it was develop following a set of rules of software development in a operating system.
VLC: This media player also use Qt.
Skype (for Linux): This program also use Qt.
It means that those programs will never look native on Lubuntu, because they do not use GTK on its interfaces.
So, to change the font of this programs will need to use another program that is used to modify Qt interfaces.
Like Zignd said this is because these applications use Qt to draw the application UI.