Under Foreign Tax Credit (1116), on the tab that you made your entries for G/L, you'll see a tiny x in the top right corner.  Click on the x and that tab will be deleted.  Poof, gone!

If you want to just remove the foreign source income entered on that page, under the section "Gross Income Within Country", scroll down to Other Foreign Source Income, and remove/change your entry on the next line for Income (Click on button to expand).