Selecting lexer from bottom pane doesn't work

What steps will reproduce the problem?
1. Open a file that Editra doesn't auto-assign a lexer to based on extension
2. Attempt to select an alternate lexer via the bottom pane

What is the expected output? What do you see instead?
I expect to see the file re-lexed+highlighted and the lexer listed in the 
bottom pane to update. Instead, the lexer listed in the bottom pane returns to 
its previous value and the file isn't re-lexed.

IMPORTANT!!! Please answer these questions for any and ALL bug reports

What version of the product are you using? On what operating system?
0.7.12 / Arch Linux x86_64

What method of install was your version installed with (Binary/Source)?
Source (AUR package 'editra')

If from source: What version of python and wxPython are you using?
2.7.3 and 2.8.12 respectively.

Please provide any additional information below.

Note that selecting lexer via the 'Settings->Lexers' menu DOES work, in 
contrast to this method.

Original issue reported on code.google.com by 00a...@gmail.com on 15 Sep 2012 at 7:03

PiRSquared17 / editra

Selecting lexer from bottom pane doesn't work #764