Erratic cursor when using F11 key in VB.net

[jherndon]

(Note: I mention a Do Loop here because that section of my code is primarily where i first noticed the problem. The code is actually several thousand lines long.)
After setting a breakpoint in my VB.Net code (VS 2003.Net), then advancing through the code using the F11 key once execution stops there, the cursor seems to jump erratically through the code, sometimes jumping one line, then three or five lines, or seven, even jumping past the end of a Do Loop and into code past the loop and into code that it should not be in. It eventually ends up back inside of the Do Loop. I have an integer (i) that is set to a value of zero just before the Do line of code and that is supposed to increment by 1 just before the Loop line of code (to eventually end the loop). It is never incremented. The result is that as long as I keep pressing F11, the cursor continues to "hop" thru the code, never finishing. The integer variable i is never incremented past a value of zero, and the cursor never really follows the instructions of the code; that is, it never follows any "If" instructions or "Do While" instructions, etc.
This is the first time I have ever seen this. Normally I can follow my code precisely where I have written it to go.
Any comments? Has anyone ever seen anything like this before?

[Phil Weber]

I have seen it before, when stepping through source code that didn't match my executable. Are you sure the code you're running was built from the source you're debugging?

[jherndon]

Phil,
That must have been it. I checked the Configuration Manager and under the Debug Active Solution Configuration, the Build check box was unchecked for some reason. I don't know how it got that way because I know it had been checked before (right up until this started happening - what a coincidence, huh?). I checked the date/time on the exe file in the bin folder and it was a week old, indicating that it was not being rebuilt when the program was running each time. Anyway, many thanks for the memory jog for suggesting where to look. It solved the problem.
John