* gnus-agent.el (gnus-agent-possibly-alter-active): New Function.

	* gnus-agent.el (gnus-agent-possibly-alter-active): New Function.
	(gnus-agent-regenerate-group): When necessary, alter the group's
	active range to include articles newly recognized as being
	downloaded.
	(gnus-agent-regenerate): Removed code that updated the agent's
	active file as the new gnus-agent-possibly-alter-active function
	obsolesced it.

	* gnus-cus.el (gnus-agent-customize-category): Added missing
	agent-disable-undownloaded-faces parameter.

	* gnus-start.el (gnus-activate-group): Backed out my 2003-11-29
	patch as it was too late at adjusting the active range.
	(gnus-get-unread-articles-in-group): Added call to new
	gnus-agent-possibly-alter-active to adjust the active range.