Don't think of FileMaker in terms of a "project" but as a "document". Other development environments work in that format - a project file with all of the various bits available as long as the project is open. You're not in Kansas anymore. FileMaker isn't that type of environment. Your workaround works but I'd try to get in the habit of not closing the document window.
And don't forget there is a script trigger for on last window close.
FileMaker won't let You 'close' layouts - but windows (-:
Go to the file options (file menu) and check the tab 'triggers' -> there should be one called 'last window close'. That one can be unchecked. Keep in mind that this trigger will probably make sense, maybe altering the script behind that trigger would be better
When working with databases, closing a window by clicking on the red 'X' on top right is not always the best method, although very common on Windows OS. It's better to minimize FileMaker or the window - as long as You don't want to quit
Since a layout belongs to a table (table occurence...), it makes sense to have that layout open when scripting or defining fields, etc -> the context (tables..) is visible. With only one table it might be not so important - but with several tables..
Thanks guys, helpful hints - it was an observation and a description of how a "new-guy" has derived a methodology that could be useful to other new guys.
That might have been the intent.
But it doesn't work; and building a structure based on illegal characters isn't isn't really a recommended practice.
Hiding context while developing will only introduce confusion and errors.
Hopefully you have entirely abandoned the approach and moved on.