Edit windows can be resized.
To resize an Edit window, move your mouse above the horizontal seam line between tracks. The horizontal seam line is the line that separates 2 tracks. Click on the horizontal seam line below the Edit window you wish to resize. Drag it downward to make the window larger. Drag it upward to make the window smaller again.
You can also resize the View window of the master track. (The View window of the master track displays the waveform of the mix).
To minimize the size of a track (and hide it's controls and effects), click on one of the graphical screws in a corner of the track's rectangle. The track rectangle will shrink to a minimum size allowing more window space for other tracks. To make the track normal sized again, click on a corner track screw again.