Check if a transcription file is already open in PE

[git-debase-verbose]

Current behavior (tested on Win 11 using the latest preview version from 04.09.2025): whenever I open an EXB file by clicking on it in Coma or by navigating to the corresponding folder on my system to do the clickety-click from there, a new PartiturEditor instance is created to load the transcription. In principle it means that I can open the same transcription as many times as I have clicked. Not sure if this is supposed to be a bug or a feature. In any case, if I happen to open the same file twice, and will then make different changes in different instances of PE and save both, changes made to one copy would be overwritten (here PE does not check whether the transcription I'm working on has been changed by a different process in the meantime).

Would it be possible to implement a check to see if an instance of PE with the same file loaded is already running - and if true, direct the user to it (or pop-up a message along the lines of "Do you want to proceed? This EXB is already open.")?

[berndmoos]

I guess a check and a message if the same file is already open should be doable. Otherwise, the multi-document behaviour is something that will need to be implemented in OS specific ways, which will make it difficult. I will look into it.

[berndmoos]

As a first attempt, I am putting a lock on all files in the PE that are opened via the system (i.e. double-click or from Coma or from EXAKT). The PE checks if there is a lock on a file which it is meant to open. If so, it will display a message and terminate PE.

[berndmoos]

(Tested only on Windows so far).
The behaviour now is: every file that is opened via the system gets a lock. You can then not open another instance of the PE in any way (i.e. via the system or via a running instance). This is what will happen if you try:

[berndmoos]

This isn't sufficient, though:

• You can still have more than one instance of the PE open and use File > Open to have two copies of the same file open
• If a file is locked while opening, the lock should go away as soon as you save it under another name. It doesn't yet.

[berndmoos]

I prefer to make that an option (de-selected by default). There are too many scenarios where you will not want the file to be locked.