SerialEM has many controls and status indicators arranged in a set of control panels to the left of the main image window. Here are the common features of these panels:
A panel can be open or closed with the +/- button in the upper left corner. When it is closed, you will still see the title and +/- button.
Many panels are divided into two parts, with the lower part containing less frequently used controls or option settings related to the main purpose of the panel. This lower section can be opened and closed with the +/- button labeled 'Options'.
A panel can be detached from the column of panels and turned into a free-standing window that can be positioned anywhere on the screen by pressing the 'F' button. Once a panel has been floated, it can be docked back into the column by pressing the button again (now labeled 'D').
The '?' button in the upper right corner will open the help page for the control panel.
The state of control panels will be saved with your Settings and restored when you restart the program (except the montage panel, which always starts closed).
When you click the mouse on a control or on the background of a control panel, the panel will almost always restore the keyboard focus to an image display window, so that the program will still respond properly to hotkey input. There are a few pixels where this will not happen: the middle line of spin button controls, the periphery of the brightness/contrast sliders, and the title bar of a floating panel. If SerialEM loses focus and its title bar goes gray, just click in the title bar or in the main image window.