Xojo is getting pre-emptive threading.
opt-in via Type property and can be changed at runtime.
Not recommended for beginners since you need to use Mutex and Critical Sections.
Xojo Inc. will go through framework classes to make some of them thread safe, so you can use them safely in the preemptive threads. Also add-on vendors will have to check which classes and be adjusted to support this.
You will probably play with this and report problems where it crashes.
Don’t touch UI from preemptive threads! This will raise exceptions or crash.
Debugger will only do cooperative threading, so preemptive only works in build applications.
This is kind of a surprise as it hasn’t been on the roadmap!