Note that this is due to the open parenthesis. If you close it or don't open it, a tooltip will appear (see attachment).
I'm not sure the tooltip would actually be that helpful in this case if the parenthesis isn't closed... While you're typing the method name, the parameters are shown in the auto-completion list. When you open a parenthesis, a tooltip similar to
[Ctrl+Shift+Space] immediately appears. This works while typing, without having to use the mouse or hover over it.
This handy function does not show up any more and I cannot find any option to fix it.
I have Laz 4.4.
What version were you using before? I checked
4.4,
3.0, and
2.2.6, and the behavior is the same everywhere.