Many of the default Ubuntu desktop themes come with a 1 pixel-wide window border. This makes it difficult to resize your windows*
You can increase this window size by editing the parameters for your theme. First off, you need to figure out which theme you’re using. In many themes, you’ll find this at:
System -> Preferences -> Look and Feel -> Appearance -> Theme tab.
Once you know the theme, open a terminal and edit the file that defines it. For this example, I’m using the Ambiant-MATE theme with the metacity window manager. Thus, the file I want to edit is:
/usr/share/themes/Ambiant-MATE/metacity-1/metacity-theme-1.xml
You’ll want to be root to do this. Look for the frame_geometry_normal section (usually the first), and change these three lines from 1 to a larger value. I found that 4 pixels is adequate:
<distance name=”left_width” value=”4″/>
<distance name=”right_width” value=”4″/>
<distance name=”bottom_height” value=”4″/>
Save the file, then you need to log out and log back in so your window manager restarts. That’s it!
*Unless you use the Alt + Right-Mouse-Button or Alt-F8 tricks, but those are not commonly known.