When you switch directories in the "Save As..." dialog, in addition to changing the directory name (in the pulldown) and the directory contents (in the main pane), BlueJ updates the"File Name:" field to have the name of the directory. This is a bug, because if you then click in the field and type the filename you want, it tries to place that filename in the parent directory. You have to first type a slash, and then your filename. This is merely annoying for experienced users, but actively confusing for beginners.
This could be fixed by:
- ending the directory name in "File Name" with a slash, or
- making the first click in the File Name field cause the whole field to be highlighted (as it is when Save As is first opened), or
- leaving File Name blank or having it contain the current name of the project, without dirpath (this is my preferred option).
I am running BlueJ 2.2.1 under Linux.