Some time ago I had trouble with Delphi's debugger. When I stepped through a source file with Delphi's debugger, the debugger was out of sync with the source file. For example, the debugger stopped on blank lines in the source file. In other words: the debugger was on another line in the source file than where the debugger was in it's logical state.

The cause of this problem was found after some time. Some line in the source file didn't contain the correct line break. I don't remember whether a line break in Delphi must be only carriage return or a combination of carriage return and a line break. However, I solved the problem by copying the source file in Notepad and then select all text in Notepad and copy and paste it back to Delphi. Then the debugger worked correctly again.