The magical search panel
They will be your best friends (there are two of them, one on the left panel, and one of the right panel), you will use them all the time.
To search for a specific option (e.g., typo, border, color)
To find the modifications you've made
To find advanced options, like the position, the z-index or the overflow properties. (click on the Icon so the search will include the advanced options).
You can change the unit of a value by clicking on it, so the list of all available units will show up, or you can simply type it when you enter the value.
For example, if you see % and you want PX, you can simply type "50px" and it will change the unit automatically. (if this unit is available for that particular field, obviously)
By default, when you have to open several popups in a row, it can look pretty messy :
In the Preferences, there is a settings for that feature, called Popup Position:
It's much more convenient now (kind of) :