The draggable bar that separates the results pane and the sql commander is too small; if you want to grab it to resize the portion of the screen each pane gets it can be tricky to get the pointer on the right spot to do so.
I'm sure many can attest to this annoyance.
I will open a new ticket that the bar should have more pixels making it easier to locate.
We have just released DbVisualizer 9.5.1 with larger dividers between components.
Easiest to upgrade is to run Help->Check for Update in DbVisualizer. An alternative is to download from http://www.dbvis.com.