| Overlays and comment display
A channel selection window appears in the lower left (the button for the active channel is switched off). Select any or all of the available channels, then click the'custom' or 'Done' button.
If you clicked the 'custom button, you can select two additional options (if you clicked 'done', the program defaults to dashed lines and overlay on all subsequent plots).
After you click the 'selection OK' button, data about the selected channels are drawn in colors corresponding to the color code in the lower left window, and the overlay operation itself begins in the plot area.
An easy way to do a simple overlay (one channel only, no options for dashed lines or subsequent plotting) is to hold down the command key while picking the desired overlay channel from the pop-up menu in the upper right corner of the plot area. This can be repeated as often as desired for additional channels.
Alternately, you can do a simple overlay by holding down the 'option' key and selecting the desired channel from the main keyboard number keys (not the keypad).
SHOW COMMENTS Toggles display of the file's comments in a small window. If you click on this window, another window opens to allow editing of the comments. Comments can be essentially unlimited in length (32 K of characters), but you'll only see the top few lines in the comments window. Show block instructions Toggles display of instructions for selecting blocks and switching screen views (normally shown in the lower right of the display, but it can be removed with this command if it gets annoying).