Alternatives for "SelectedTab [Set]"

We are updating our software to .Net 6, and I noticed some action aren't available anymore.

SelectedTab is still availible but doesn't work anymore.

Logs say: Unable to find the object WinFormsObject("tabFinancieel"). See Details for additional information.

However when manually selecting the tab and changing back, using SelectedTab does work.

Almost like the tab doesn't exist if not activated before. when restarting the program it no longer works.

I tried 'set_SelectedTab' which also does not work.

I don't want to use 'SelectedIndex [Set]' since the order of the tabs can (and does) change.

Is there any other action that might work in the situation?

Or is there any thing my developers can change (small changes only ofcourse) about our code to stop this problem?

Thanks!