Quartus freezes when selecting text in editor

I have the problem that Quartus II sometimes freezes when I select text in the built in text editor. Quartus then does not react to anything except ctrl+c.

I have seen this with Quartus II 11.1sp2, 12.0 and 12.0sp1 on Fedora 16.

At first it appears to happen randomly, but I have found a way to reproduce reliably (with 12.0sp1):

1. create a verilog file in a project

2. add the line "reg [7:0] foo=8'd0;"

3. save

4. select the last zero (marked in blue) with your mouse from left to right

5. Quartus is frozen

After some more testing it seems to be connected to the "Highlight similar instances of a selected word"-feature. When it is disabled in "Options"->"Text Editor", Quartus does not freeze.

Can anybody else reproduce this?