Erratic SplitLayout behavior: why does the separator keep jumping around?

I am using a SplitLayout to display - well - two components (left and right).
Depending on the selection in the left panel I am displaying different forms in the right panel. Pretty trivial one would think.

But why - the heck - does the splitter (the separator) keep jumping left and right when I change the right panel’s content?
I find that most irritating and absurd! I would have expected that it only moves when the user repositions the splitter manually (or it’s changed programmatically) but obviously not so.

Can one somehow enforce that the splitter remains where it is when changing the content of one of the panels?

I tried to work around this behavior but one can only set the current splitter position but not query it!
And - while one can attach a DragendListener to the SplitLayout the DragendEvent does not reveal the current splitter position. So one can’t even memorize that position beforehand and set it back to that value after the change. :frowning:

Furthermore, as I had to learn one has to give the splitter-position in “percent of the width of the second element”.
Thus, to place the splitter in the middle, one does not have to pass 0.5 or 50(%) - as one would guess - but 100(%). ||-(

Pardon me, but what had the programmer smoked before hacking up this component?