Don't select content when field gets focus

[sunmachine]

When I click into an edit field of the parameter configuration area, its current value is selected entirely.
Since the highlighting is currently hard to see I often overwrite the value although I just want to add something at the end.
Or I'm clicking straight on the right spot where I want to edit the value, begin to type and overwrite the value instead of inserting something.

So I think it would be better to not select the current value as soon as you click into a field. That's how it works in most applications anyway AFAIK.