Error in TCustomGrid, how to rebuild libraries?

I've found an error in the VCL library (BCB4) source about the object
TCustomGrid. It's impossible to recognize when the user ends editing the
cell in case he clicked another cell of table while in entering mode. In
event MouseDown handler there is wrong line 'HideEdit;' that doesn't turn
off the EditorMode property before the SetEditText event handler called.

How can I rebuild the library If I correct this line?

Thank you. Sorry for so bad english.
I'll hope to receive the answer.

Alexander Kuznetsov
mr...@mail.ru