I do debugging in Delphi 2007 IDE. When I move cursor on array variable it shows hint on it. To see more detail array members I need to move to sub hint. The same situation is when I need to see object fields and subfields. Sometimes it is very tricky to move mouse without getting out of hint coverage area. Is it possible somehow hold hind mode while getting to sub hints?
I recommend you add a Watch to the specific variable and then use Watch List for inspecting variables/components data.
The main advantage of Watch List is that you can monitor several different variables at the same time. And you can see objects properties in structured manner.
While debugger tooltips has some interactivity handy, they are still based on tooltip window and behave accordingly, therefore you cannot make it persistent. This is by design, debugger tooltips are supposed to allow quick examination of variable value and no more else.
When you need to examine a variable more closely and you are actually interested in the deeper details like private members, you could examine your structured variable in the debug inspector window. (one per variable). You can open many such windows, they are persistent during debugging session and can be docked to your debugging layout. Note that having 
button pressed continuously retrieves property values with getter method.
For debugging aids which are persistent across the debugging sessions and are less detailed see @SilverWarior's answer.
