I rarely have less than 3 open at any one time covering a range of languages:
Java , C, C++ , C#, Cobol ...
What's really confusing is when you write a correct statement in the wrong language
e.g. in the Cobol IDE, I wrote:
Temp = 1;
and then you wonder why the compiler complained!
If you don't have your orientation correct, it's a puzzle because it *looks* correct. The moment you realise you are in the Cobol IDE, the penny drops.
The correct statement is of course:
Move 1 to Temp.