How exactly did you try it?
I added a Panel in a layout, set the Height to 3000 and no problem!
What exactly do you want to put onto your layout?
Yeah, you can set the height in properties window, also in code.
But, I was dragging the panel longer and longer, until it reaches 2040, then I can't drag it longer any more.
Also, if you put a new view in designer window, where the top value is larger than 2040, or something like 2048, which is indicated by the gray area,
then you can't drag the lower handle downwards, but you can drag the upper handle.