TL;DR
Instantly craft whatever item you are pointing at.What ?
While in Game instantly craft the item your cursor is on. Maybe use "Shift + Left Click" to instantly craft 1 item and "Shift + Right Click" to craft 5. All without ever entering the crafting menu. Just as "Q" has been implemented to instantly select the item you are pointing at, now instantly hand craft 1 or 5 of that item.
Why ?
When you want to craft a Boiler, you hit "E" , select "Production" icon , click on "Boiler" , hit "E" again to exit. 4 steps. Not hard to do, but it can get repetitive. Need another Boiler? Just "Shift + Click" on an existing Boiler from your factory and instantly start hand crafting one. Done. Sometimes after playing Factorio for several hours you may even forget for a second where a certain item is located in the crafting menu, or you keep going to the wrong page as a reflex. But Just the Opening and closing of the craft menu can be repetitive. Avoid going into the menu completely for crafting basic items. I think this can improve on the game play flow and reduce some of the in and out of menu steps when manual hand crafting.See more about here:
viewtopic.php?f=6&t=27087 How is This Board Working? Revision #3
That seems like a super simple mod to make....
(note to self - that's a really good idea; hate when I alt-tab and lose icons too... backslash looks like a good target key)