Tempo track responds really slow

As in the header: when I drag the tempo up or down in the tempo track editor, it responds really slow. It looks as if it freezes for a few seconds and then goes to a value somewhat near the value I want to get. If this one isn’t correct - and since it doesn’t respond to dragging at all at first, it always lands on a wrong value, because you don’t know how much you move the line -, I have to repeat this several times, which obviously is very annoying and pretty time consuming.
Is this a known bug, or is it a setting in the preferences f.e. which I have to change?