"Could not include..."

An interesting gotcha ate my lunch tonight:
I made a quick program to test a portion of code using DT_INTS-18.bas and I couldn't get it to compile.
I was in MCS and already compiling the mother program in a different tab, but the child would throw the error: "could not include DT_INTS-18.bas".

I tried all kinds of things and had no answer. One would find the include and the other would not! A couple of hours later, I needed to clear some of the programs off of my desktop to find another icon and there was the copy of the test program. It couldn't included it because it wasn't in the MCS folder with the INT program. I had done a "save as" on a earlier file to the desktop and never thought about it. My test file went there and I didn't realize it.

Just a tidbit that might help some day.

Bo