In case I have char[] array in my heap dump and want to see what's in it, I have
to use the tooltip over the value cell in the HeapWalker's instance view.
But for large char arrays, the tooltip behaves erratically - just blinks shortly
and disappear on each modse movement over the table cell.
Moreover, there are few more problems with this:

First, I may need to see bigger part of the char array than what can fit into
the tooltip.

Second, it seems that Swing behaves poorly when you ask it to "measure" really
long String - it caches the largest used char array in
sun.swing.SwingUtilities2, which may cause a memory hog - ever looking at 2MB
char array means SwingUtilities2 will keep 2MB copy of the array forever.