This regression appeared in Flex SDK 4.13. If fdb says "Breakpoint not set; no executable code at line ..." then VM must stay in suspended state, but it resumes. As a result IntelliJ IDEA users who have at least one breakpoint at the line without executable code can't debug the app at all.
1. Take any simple AS application, for example, attached Main.as and compiled Main.swf
2. In Terminal run [Flex SDK]/bin/fdb, type 'run' and Enter
3. Launch Main.swf
4. Debugger will attach and fdb console will suggest to set breakpoints. Type 'break Main.as:1' and Enter
5. fdb says 'Breakpoint not set; no executable code at line 1 of Main.as#1', VM resumes, application runs. The problem is that the client has no chance to set other breakpoints after that.
Expected result is that after saying 'Breakpoint not set...' VM remains suspended, fdb prints its prompt (fdb), so client is able to enter more 'break' commands.