mouse stucks in "drag" mode

Can you explain what you mean about "dragging mode"? What specifically are you doing, what do you expect to see, what happens instead?

Hmm, I've never heard of that happening. Does the mouse still function correctly? If not, can you describe something in particular that doesn't?

Mouse broken? We had that several times already...

No one else has reported this, so it's impossible to track down the problem.

What operating system do you use? What kind of mouse? You you actually use the drag feature in other programs?

I have the same prob. Only with Musescore (I'm using 2.1.0). My operating system is Ubuntu 18.04 but have had the same prob with earlier versions of Ubuntu. My computer is a Dell Inspiron 13-537. When the prob happens, the Musescore window drags around with the mouse (as if in grab mode with the cursor as a hand), and I have found no way to release it other than rebooting. Very annoying and has been going on a long time (prob'ly going back to the days of my Microsoft Surface Pro running Ubuntu 16.04 if I remember correctly). I haven't been able to notice anything that triggers it consistently. I'm writing this now in my browser window with no prob while my cursor in Musescore is misbehaving like this. The prob is specific to Musescore -- not affecting my browser or any other ap.

MuseScore 2.1 is very outdated nowadays, 2.3.2 is the lasst MuseScore 2.x and with MuseScore 3 we're meanwhile at 3.3.4 (3.4 expected shortly)

Point well-taken Jojo. 2.1 is the latest official version of 2 supported by Ubuntu 18.04. I'm reticent to go with a more recent "rogue" version. I tried Ubuntu 3 when it first came out, but had probs using it with a secondary monitor. Sizing probs, with key control structures unavailable off-screen. Maybe I didn't give it a fair chance. I backed away from Musescore 3 when discovering that anything it saved wasn't readable in good-old Musescore 2, knowing that once I get entrenched in Musescore 3, there would be no going back. Apart from the cursor mishaps, it's fantastic software. The community is helpful (almost any question I've had about using Musescore, I've found already answered), and the library of shared music is a wonderful resource.

FYI, the AppImage you can download right here on MuseScore is not "rogue", it is in fact the only version of MsueScore actually officially supported by the MuseScore team themselves. The versions in the repositories are generally built by third parties and are out of our control. So you really are best off using the AppImage in general. The fact that it also allows you to get the most recent version is a bonus. As for not being able to open MuseScore 3 scores in MuseScore 2 that's true, but there should be no reason to do so, either. If you feel you might possibly need to open a score in MuseScore 2 for some reason, simply save the MsueScore 3 version under a new name (and you are prompted to do exactly that).

Thanks Marc. I mean "rogue" in the sense of using out-of-registry aps. I've had probs before doing that sort of thing (with other aps) so I've been trying hard to stay "clean" using only the Canonical-supported repositories and LTS versions of the op system. That said, I'm downloading the 3.3.4 AplImage now on your advice. I've seen enough to know that you are very highly respected in this community. Ability to save in historic mcsz format is a big plus so that I can give Musescore 3 a fair whirl without committing to abandoning Musescore 2 before I'm ready. I posted today on this forum for the first time and already have my answer. All quite impressive.

FWIW, in my days as a CAD Support engineer I vaguely remember such issues with mouse pointers no changing back to a simple arrow. It always turned out to be a kind of miscommunication between application and underlying OS/middleware. Both reports are using Ubuntu as OS and to my knowledge Ubuntu is Gnome based so QT is not their primary libraries. As Amijai already stated, it could be an Ubuntu issue.
Did you reported this issue to Ubuntu too?

Same issue, Dell laptop on Ubuntu and v2.1.0 installed from the Ubuntu repositories. Gets stuck on hand screen scroll, moving text on page. Right clicking and esc sometimes gets it to release but its very annoying! Looks like its a bad combination. :(

Reports for MuseScore 2 won't help in any form or shape, no fixes for that would ever be made.

There are definitly newer version available for Ubunto (IIRC 3.2.3 is available, the maintainer hasn't yet come around to update to 3.3.x or 3.4.x), and there's always the latest version available as an AppImage.

Seems so far all reports here are about MuseScore 2, so I'll close this as "Won't fix"

Same here. On a fresh 3.4.2 install on a dell XPS. I had to reboot.

See #318613: [Ubuntu] mouse immediately enters, stays in clicked state on launch for a similar (?) issue in 3.6.2 (also on a Dell XPS and Ubuntu)

I'm using
Dell XPS 13 9360 laptop,
Ubuntu 20.04,
Musescore Appimage 3.6.1
This problem ALWAYS happens. The work-around is to middle click to release the hand and return to standard pointer.
If you are using a touchpad you will need to install gnome-tweaks and configure the touchpad to middle click with a 3 finger tap - it's an option in Tweaks.
This is definitely a bug, just not sure where the bug is - Dell, Gnome, Musescore or all three.
It does NOT happen on my desktop Ubuntu 18.04. I suspect the problem has something to do with the Dell laptop.

Hi all, unexpected update courtesy of this StackExchange link I stumbled upon: https://unix.stackexchange.com/a/527310

If you experience this bug on a Dell XPS or other touchscreen laptop, tap your touchscreen. I'm still kind of breathless after tapping mine just now and realizing my session had returned to normal. I found the above post while wondering if the issue wasn't with Musescore, but the interaction between Qt and the Ubuntu kernel. To my surprise, googling "Qt app stuck in mouse down" turned up this result, which implies that the source of the bug is likely one layer further down than Musescore's UI code.