Bolton have completed the capture of former Crewe striker Max Clayton on a three-year contract.
Felix Magath has been sacked by Fulham, with Kit Symons taking over as caretaker manager.
Seaborne has won three and drawn one of the four matches he has played in since making the temporary move to The Valley.
The 25-year-old was forced to sit out the final match of his original loan spell, last Saturday's 2-2 draw against Brighton.
But Seaborne will get the chance to extend his unbeaten run in the Charlton team after a fresh deal was struck.