Handle different look and feels in JInternalFrameOperator

There are multiple issues in different L&Fs.
In Motif L&F:
 - JInternalFrame doesn't has tooltip text for minimize and maximize buttons.
 - It doesn't has close button.

In Nimbus, Motif and Windows Classic L&F:
- We have to press two times on desktop icon to restore it to previous state.

GTK L&F:
There is a deadlock issue - (stack trace added in below as a comment)
There is a ClassCastException while invoking some constructors(stack trace added in comment)