SE exits on double-click on a word under Linux (using Mono)

[GoogleCodeExporter]

(enter only *ONE* issue in each report)
What steps will reproduce the problem?
1. Create a new line
2. Write at least one word
3. Double click on the word to highlight it in the "Text" area

What is the expected output? What do you see instead?
It not only highlights the word but basically does the same as if I wanted to 
close the application: SE simply exits or asks if I want to save the subtitle.

What version of the product are you using? On what operating system?
SE 3.3.4 rev. 1785 under Linux Mint 14 KDE

Please provide any additional information below.
I installed Mono from the official Ubuntu repository, together with packages I 
found mentioned on various forums that were needed so that SE can run. I'm not 
sure if an additional package is required or it is a bug in the application 
that Mono brings to the surface.

When this bug happens, I get the following output in the terminal:

System.NullReferenceException: Object reference not set to an instance of an 
object
  at System.Windows.Forms.TextBoxBase.TextBoxBase_MouseMove (System.Object sender, System.Windows.Forms.MouseEventArgs e) [0x00000] in <filename unknown>:0 
  at (wrapper delegate-invoke) <Module>:invoke_void__this___object_MouseEventArgs (object,System.Windows.Forms.MouseEventArgs)
  at System.Windows.Forms.Control.OnMouseMove (System.Windows.Forms.MouseEventArgs e) [0x00000] in <filename unknown>:0 
  at Nikse.SubtitleEdit.Controls.SETextBox.SelectCurrentWord (System.Windows.Forms.TextBox tb) [0x00000] in <filename unknown>:0 
  at Nikse.SubtitleEdit.Controls.SETextBox.WndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0 
  at System.Windows.Forms.Control+ControlWindowTarget.OnMessage (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0 
  at System.Windows.Forms.Control+ControlNativeWindow.WndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0 
  at System.Windows.Forms.NativeWindow.WndProc (IntPtr hWnd, Msg msg, IntPtr wParam, IntPtr lParam) [0x00000] in <filename unknown>:0 

Original issue reported on code.google.com by notarg...@gmail.com on 20 May 2013 at 5:32

[GoogleCodeExporter]

I've searched for this error message on the web and it appears to be a bug in 
Mono. If someone had an idea of a workaround (other than avoiding double 
click), I'd appreciate it.

Original comment by notarg...@gmail.com on 4 Jun 2013 at 3:37

[GoogleCodeExporter]

SE has moved to GitHub - please re-add this issue at GitHub if it's still 
important :)
https://github.com/SubtitleEdit/subtitleedit/issues

Original comment by nikse.dk@gmail.com on 4 Feb 2014 at 5:24