CA-139888: Changing window size should not change the number of items minimized in Outlook-style navigation panel

When the navigation panel is resized, we need to preserve the height of the bottom panel, by recalculating the splitter distance.

Signed-off-by: Mihaela Stoica <mihaela.stoica@citrix.com>
Merge pull request #113 from MihaelaStoica/CA-139888

CA-139888: Changing window size should not change the number of items mi...