@Beatrix W If you don't invest time to find out what is causing the slow down the problems likely won't get fixed. And the problems with the debugger haven't been mentioned before.
Xojo doesn't have time to port back fixes.
Sorry, Trixi, but that is just not a reasonable perspective. Xojo isn't a free, open source product. We pay to be able to use it and we are justified in expecting it to function properly. It's not the user's job to determine why a product does not work as expected - even more so in a development environment. As users, we don't have access to the product's source code, so we only see what we see. What happens between when we type CMD-B and the app launches? We have no idea. How can we do more than report what we see.
Imagine if you were required by your car manufacturer to determine the exact cause of the noise you hear when driving before they would fix your car. Or that your doctor require that YOU completely diagnose your problem before they will determine what your treatment should be.
Granted, some of us go outside the norm and run debuggers on top of debuggers (strace, kdump, Instruments, etc.), but that's not our job as "users" and "customers". At worst, we should be asked by the product company to allow remote access to our systems to try to debug using their source code (and the Xojo Remote debugger would allow that easily for them). I've made that offer many, many times in my feedback reports, but I've never need taken up on the offer.
It also worries me that so many reports in the feedback system are still marked as "Needs Review". While these may have been touched by someone within Xojo's team in some manner, all that we see on the outside is that our submission has gone unnoticed.
As for Xojo not having the time to back-port, that's what I meant with my stating that I "wished" that they had an LTS model and the staff to do that.