Strange problem when editing .vhd files on Ubuntu

I keep having a strange thing happen when I'm editing .vhd files in quartus ii 64-bit version 13.0.0 build 156 04/24/2013 sj web edition (using this version for Cyclone II support) on ubuntu 13.10 64-bit.

fault 1: While typing, occasionally my view will start jumping to one point on the .vhd file every time I press a keyboard key when the display is focused on another region. The only solution is to close and re-open the source-file. I'm not sure why typing would automatically change the focus.

fault 2: This is more serious. Occasionally I'll find sections of a source file re-created/copied at "random" locations in the document. Unless there's some strange shortcut I'm not aware of which copies segments of my code and pastes them at another seemingly random point in my VHDL file, I'm really not sure what could be causing it, other than some sort of file corruption.

Say, for instance, my code is:

The quick
brown fox
jumps over
the lazy
dog

I'll be editing and all of a sudden I'll notice (often when I scroll up to another section) something like this:

The qufox
jumps over
the  ick
brown fox
jumps over
the lazy
dog

Is there a history of this with any versions of Quartus/Ubuntu? I haven't noticed it with any other software on my computer, so I presume it's a Quartus problem.