Sub-window hidden behind another window... any way to retrieve other than minimizing? My one grievance with how MacOS handles window management is that sometimes windows get hidden behind others and do not appear in the dock as they are not minimized. The only way to find these windows again is to minimize the windows in front of them. Is there a quick way to see all windows like in Microsoft Windows, where every window gets a spot in the dock? 

For example, you are using the Mail app. You start writing an email. You start doing work in other windows without minimizing the message draft window. Lets say you open up 3 or 4 other windows. The only way to find that message draft window is to minimize those 3 or 4 windows. Is there a way to make the message window always appear in the dock so you can retrieve it from there?
In current versions of macOS (the last few, in fact) allow you to tap the F3 key to show all windows of the current application. On MacBook built-in keyboards and Apple's own keyboards the F3 key has an odd looking icon that represents this. Similar to the F4 grid of squares that brings up Launch Pad.

Windows will shrink in size so they can appear all together on screen allowing you to tap on the window you want to restore the App with that window frontmost.