The fileplan view has three separate panes:
Each of these panes can be resized to suit your display and preferences. Position the mouse over the vertical lines between each pane until a double-headed arrow appears. Click and drag to resize as required.
The Explorer and Preview/Details panes can also be hidden entirely by clicking white caret in the top navigation bar.
If you are moving your window between different resolution displays, you may find that the side panels have disappeared completely and clicking the caret does not appear to have any effect. The most likely explanation is that the Results pane has been resized to take up all available space on the screen.
- position your mouse at the very edge of the display until the pointer changes shape (you'll probably only see half of the double-headed arrow that remains inside the window).
- click and drag to resize to the desired width.