When scrolling up or down, using CTL up/down-arrow the carret position stays fixed and can be scrolled (way)out of the
visible window. When you have finished the scrolling to the place you want to continue editing, the first thing that
happens when you use the arrow keys to fine position the carret, is that you scroll right back to where you started.

I suggest that the carret position gets restrained to not leaving the visible window e.g. when CTL scrolling down, the
carret will initially scroll up, following the text, but will not be allowed to scroll above the first line in the
visible window.

As it is now, you are forced to use a mouse click after the CTL scrolling, which is annoying.