interesting error: new form has black line across it, how do I get rid of it

Question

I was creating a new form and my IDE crashed, or it was having problems, and now every time I create a new form it has a black line across it. The black line is not something I was adding, it appears to be the black line from the top of the form getting painted in the wrong place. The interesting thing is that every time I reload the form the line moves up until after the 5th load it disappears. How do I stop this happening? I have tried build, rebuild, clean solution (restart visual studio) but it is still there, it isn't consistent either which also annoying, any ideas?

Answer 1

The way the line appears overtop of the window (it goes over the border) makes it look like it's probably outside of the Designer-generated code.

Some exploratory coding:

1. Make a backup!
2. Try commenting out as much code-behind as possible. Test if it recurs with only the designer-generated code.
   • if it doesn't, then slowly uncomment your code-behind. The highest-risk code is anything that either directly manipulates the Graphics system.
   • if it does, then try commenting out different control declarations until it goes away (you'll be tweaking generated code, so this is where a good backup is critical)

To help test, can you comment out any code-behind so that it's only the Designer-generated code and see if it still occurs?