Intellisense stopped working in a certain case

I was working a on program using SharpDevelop 5.5 today and was writing this block

                for (int y = 0; y < 5; y++) {
                    for (int x = 0; x < rect.Width; x++) {
                       
                    }
                }

and when I got the x < rect. part it didn't show me any autocompletion.

I tested the exact same situation in 4.4 and there the intellisense didn't break, so this is an 5.1 issue.

The whole file is here https://dl.dropboxusercontent.com/u/59546146/MainForm.cs (line 277) and for testing is it enough to remove the ".Width; x++) {" part of the line and just enter a new . behind the rect variable, 4.4 shows the autocompletion then, 5.1 doesn't.

Edit: since I guess that the .cs alone won't work that well for testing as the whole form for it is missing is here the whole project in the current state https://dl.dropboxusercontent.com/u/59546146/ED_MiningOCR.zip