Random windows with caption containing "ILSpy" activated and modified during ilspy startup

[tamlin-mike]

I had ILSpy.xml open in Scite, and got really confused when trying to start ilspy (from cmdline). Instead of opening ilspy, Scite opened a new tab, with a document named "I".

The only thing I can come to think of is that ilspy is trying to find a previously running instance during startup, and in error only checks for partial window caption. It then sends some random WM_* message (or shudder some DDE "verb"), that in this case results in the editor opening the aformentioned empty document.

Would appreciate if someone could have a look at it, and harden/correct the "check for running instance" code (provided my analysis of the problem is correct).