Thank you so much for all your help - much appreciated!
Sorry if I have wasted your time 
Once again - THANK YOU.
If trapping the Tab key in Keydown fixes it, then it certainly is a bug of some kind, although it seems hard to duplicate. Can you duplicate it in a small project and submit it to Xojo?
Michel:
Your code solved the problem !
Unfortunately it now causes the user’s system to beep when the second control receives focus
Any ideas anyone?
Thank you all.
You have to “Return True” after you have handled the key press in KeyDown.
Sorry for necromancing this thread…
I’m developing a desktop app, where the main GUI is setup by data from a file, placing a bunch of ContainerControls inside a GroupBox inside a GroupBox (so I can scroll the chunk using a scrollbar).
Now, the ContainerControls (which each have a small GUI on them) are added top->down, the first added at top Y, the next at top+height_of-the_one_above+margin etc.
But the Tab order is bottom first, and then it goes upwards, 5 - 4 -3 - 2 when hitting tab (and the correct order when hitting shift tab.
How can you control this programatically as I do not know beforehand who will be after me (that is done at runtime, parsing a file, adding the objects. I could probably tell each of them who’s next and who’s before during creating, should I do my own tab handler in KeyDown for this or is there some magic API i’ve forgotten about / never heard of to handle it.
Ok, go back to sleep, I solved it using a double linked list in the parent ContainerControl, that “my” ContainerBlocks inherit from, and some init code. Xojo has come far, this is really a quite productive platform. No need to spend too much time figuring out how to do things, it’s just implement, test and it works 
You dont need to do this in code. There are two command bar buttons to help with tab order. One with a number in a box (manual) and the other looks like a Z (automatic).
Does that work with dynamically added controls as well?
No. They get added to the end.
Sorry for necromancing this thread… again
I’m doing the similar thing as Totte was: Adding various ContainerControls to a parent ContainerControl.
I expect the first created CC to get the focus first when hitting the tab-key. Instead it is the last created CC the recieves the tab-key.
I suppose I could create the CC’s backwards but that is not a very nice solution IMO.
I reported this back in 2011 in this case: <https://xojo.com/issue/15947>