We have create an problem with the display of the dropdown menu, because we lowered the height and went to two line display. The position were the dropdown menu appears is incorrect.

This is displayed in the following picture.

This cause the selection to disappear when you move your mouse down to click it.
So we need to fix the position where the dropdown is displayed.

I have illustrated that in the next picture.

We need to edit this in the editor (highlighted) under Appearances tab. You need to have a look in your style.css sheet and find the area with code that shows you menu. Look for top in #access ul ul { }; this is where you can change the value to display in the right position. For me I had to take 2 times the line height +.1 to give me the right result. For you it might be slightly different, also if you want to wrap more than 2 lines this value will change accordingly.