Here's a prototype with an animation of it being used on a scheduler app.
Did some interviews and everyone said the hotbar would be "cool" or "sounds good." But I actually built out the feature and this is it. I think I'm going to scrap it, as it's too prone to error.
There's a visual to make this easier to understand.
First Option: Hotbar (left) Too prone to error. Unless someone is extremely into mmorpgs, I don't think users will appreciate the extra functionality. (See codepen for an animation of the hotbar)
Second Option: Dropdowns (top) Click the dropdown to filter groups. Click the shift to get '10 to 2' '12 to 6' etc. Then you can click multiple boxes instead of re-typing
Third Option: Click table cell This might be the most intuitive option and least prone to errors (I'm guessing).
Fourth Option: Dropdown + click table cell Instead of having the drop downs where the bread crumbs are, maybe include them in a popup menu
Best Option based on user research I noticed the place I used to work at would have the shift times in the top column instead of dates. Then the row below would have a list of person's names instead of names on the left side, they would be in the table cell. I think this just proves a simple excel interface or piece of paper might trump the fancy website I'm building.