To reproduce:

Type the following and wait for parsing to finish.

QString dupa;
dupa.toLower();

1) Don't touch the keyboard except of F1 key when needed
2) Position the mouse cursor over the "QString" and wait for tooltip
3) When the tooltip shows up press F1 - side help will show up - ok
4) Position the mouse cursor over the "toLower" and wait for tooltip
5) When the tooltip shows up press F1 - you will be switched to full help mode