While editing an assembly, if you need to quickly hide parts that are ‘in the way’, simply press the Tab button. The top component directly below your cursor will be hidden, if you click Tab again then the next part below the cursor will also be hidden, all in order. For example, in this assembly below, with my cursor on the Ace of Hearts, clicking Tab will hide the Ace Card part, then by selecting Tab again, the King will be hidden and so on.
In order to show hidden part(s) simply click Shift+Tab on the keyboard while your cursor is over where the hidden part is located in the graphics area. As shown above, any component directly below your cursor will be shown using Shift+Tab. If there are multiple hidden parts, they will be shown in reverse order. For example, below the card displayed is Queen of Hearts, clicking Shift+Tab will show the King. Without moving your cursor clicking Shift+Tab one more time will now show the Ace.
This tip can also be used in combination with the ‘Isolate’ command in order to hide or show additional parts from an isolated selection set or current Display State.