If you cannot see a window:
The window may be auto-hidden; find the window's labelled marker at an edge of the EdgeCAM window and rest the cursor on it. The window will appear.
If you cannot see a marker or the window, you need to open the window:
Right-click on the title bar at the top of any window, or right-click on any toolbar.
In the subsequent shortcut menu rest the cursor on Windows ►.
In the subsequent list of windows click on an un-checked window to open and show it, click on a checked window to hide it.
Note that in this list of windows there is a shortcut key combination displayed against each window. You can use the shortcut keys to quickly switch the window on or off, without needing the above procedure.