If you try to move a task to another project, the projects list is positioned to far down in the search window, sometimes even off screen.
Please try to log out and back into your account (we've just made some recent changes) and let me know if the issue persist.
If it does, please clarify - you're right-clicking on a task (on which view), choosing "Move to project" and then the scrollable project selection list is off-screen?
You're welcome to send a screenshot showing this issue to email@example.com and firstname.lastname@example.org
Logging out and back in has solved the issue. I'll keep in mind to try that first before posting a question.
Thanks for your help!