This seems like an elementary issue, but it's tarnishing my application. When my GUI first shows, it's a toolbar with an empty JScrollPane below it, and you're supposed to cllick Open in the toolbar, and then stuff shows up below. But when I set up the stuff below and call setVisible(true) on the scrollpane to display all the contents, nothing shows up. The only way to make it display is to resize the frame.
Nonetheless, whenever I make any subsequent changes, the GUI updates itself properly.
Why is this happening, and how can I get my GUI to repaint for sure without an ugly (unnecessary) resize?