When you are the in the visual schedule builder (VSB), looking at the Work tab, you see a canvas with all the shifts laid out showing the work assignments for each shift.
The first menu option on the upper left will open a list of work assignments you've defined for your department.
By default these are sorted by colour, so similar types of work assignments (breaks, classes, activities) will be grouped together:
But if you have a long list of work assignments, it can sometimes require scrolling to find the one you want. The listing has a quick filter at the top of it.
Click on the "Search your work assignments" input and start typing the name of the work assignment you are looking for. The list is immediately filtered:
You can then double click or drag the WA over to the canvas as usual.
To restore the list hit your Esc key.
Pro tip: To save time you can open the Work Assignment quick filter by using the keyboard shortcut Ctrl + Shift + S to enable search, then click W again to focus on the work assignment listing.