Setting a preference property while starting Eclipse not working

[UdoW]

I try to set a preference property of another plugin while starting Eclipse. I use an OSGI component which uses an event handler at the event @EventTopics(UIEvents.UILifeCycle.APP_STARTUP_COMPLETE) to change the property.
I can see the change of the property in the preferences file of the target plugin. But when Eclipse finished starting then the property is set back to its value before I changed it.
I see that the class org.eclipse.oomph.setup.impl.SetupTaskImpl changes it back to the previous value.
Why is it changing it back and how can I set it to my value while starting up Eclipse?

[merks]

Probably you recorded the preference so that it's in the user.setup. Use Navigate -> Open Setup -> User to look at it. You'll see a section like this with the preference tasks organized into groups:

You can delete the ones you don't wish to have.

You can record preferences by enabling the record button:

They light bulb button is then shown so you can initialize all the preferences before recording the ones you change in the dialog.

[UdoW]

Thanks for the explanation. How could I do this for my own Eclipse RCP application? Where do I setup the initial setting in my product build environment?

[merks]

I don't think you'd generally use this for a product.

I would expect a product would use this approach:

https://help.eclipse.org/latest/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Fguide%2Fproduct_configproduct.htm&resultof%3D%2522%2570%256c%2575%2567%2569%256e%2522%2520%2522%2563%2575%2573%2574%256f%256d%2569%257a%2561%2574%2569%256f%256e%2522%2520%2522%2563%2575%2573%2574%256f%256d%2522%2520

E.g., here is what the Platform SDK product does to configure default values for preferences:

[merks]

FYI, if you have a product with Oomph installed in principle you could pre-populate the installation.setup located here in the installation itself:

[UdoW]

I don't think you'd generally use this for a product.

I removed the Oomph features from my product and now my solution works.

Thanks for the hints.