I often use Quick Collection in Lightroom to create a temporary collection of images (to submit to a client, use in a demo, etc.). However there are times when, after making the Quick Collection, I want to convert it to a regular collection. To do so, Control-click (Mac) | right-click (Win) on Quick Collection in the Catalog panel and choose Save Quick Collection. In addition:
• Command + Option + B (Mac) | Control + Alt + B (Win) will convert (or save) a Quick Collection to a regular Collection.
• Command + B (Mac) | Control + B (Win) will display the contents of a Quick Collection. Tapping it again returns you to your previous location (folder, collection etc.).
• Command + Shift + B (Mac) | Control + Shift + B (Win) will delete the contents (clear) of a Quick Collection.