I cannot figure out how to erase the blue box around the task descriptions that are imported from MS Project.
You might have imported the text as symbol notes. It's also possible it was imported as symbol text. Here is how to determine which one was used and how to correct the issue.
Click a symbol. The toolbar changes to Current Object: Symbol.
If text appears for Line 1, Line 2 , Line 3 then symbol text was used. Follow the steps for symbol text below.
If there is no symbol text, click the small Notes tab in the toolbar. If symbol notes are shown follow the steps for symbol notes below.
Go to Format | Default Text and choose Symbol Notes.
Change the Background Color to White.
Change the Frame Type to None.
Click OK - Change Defaults and apply to all symbols on schedule.
Click one of the symbols on the schedule. This will tell you which toolbox symbol is being used.
In the toolbox, double click the symbol being used. The Symbol options dialog box displays.
Choose the Text/Date Properties tab
Under Text Background Box remove the check marks. See picture