After I first reported it it was given a case number of 176 and was supposedly fixed in build 1276. I have 10.1.1299.0 installed and the behavior is better but I still see it quite often.
Using Visual Assist 10.1.1416 or earlier and Microsoft Visual C++ .NET version 7.1.3088 in MDI mode perform the following steps:
1) Create a new C++ header file document by clicking File->New->File... from the main menubar. In the New File dialog click Visual C++ in the Categories tree, then click Header File (.h) in the Templates list, then click the Open push button.
2) In the new document type aaa
3) Create a second header file document using the procedure in step 1
4) In the second new document type bbb
5) Single click the title bar of the first document. BUG! the first document get maximized.