determining which package is 'responsible' for forcing a downgrade ?

[snowcrash+smart]

well, i spoke a little too soon :-/

here's an example of my issue<-confusion.

trying to upgrade MozillaThunderbird,

	/root# smart upgrade MozillaThunderbird
		Loading cache...
		Updating cache...
#####################################################################################
[100%]
		
		Computing transaction...
		
		Downgrading packages (1):
		  MozillaThunderbird-1.5.0.9-0.1 at i586
		
		7.7MB of package files are needed. 1.2MB will be freed.
		
		Confirm changes? (Y/n): n

it's forcing a downgrade.

checking "why" with '--explain',

	/root# smart upgrade --explain MozillaThunderbird
		Loading cache...
		Updating cache...
#####################################################################################
[100%]
		
		Computing transaction...
		
		Downgrading packages (1):
		  MozillaThunderbird-1.5.0.9-0.1 at i586
			Downgrades:
			  MozillaThunderbird-1.99.1-44.1 at i586 (downgraded)
			Requires:
			  MozillaThunderbird-1.5.0.9-0.1 at i586 (installed)
			Required By:
			  MozillaThunderbird-1.5.0.9-0.1 at i586 (installed)
		
		7.7MB of package files are needed. 1.2MB will be freed.
		
		Confirm changes? (Y/n): n

simply seems to tell me that MozillaThunderbird is required by itself
to downgrade itself.

huh?

checking what i have installed,

	/root# smart query MozillaThunderbird --installed
		Loading cache...
		Updating cache...
#####################################################################################
[100%]
		
		MozillaThunderbird-1.99.1-44.1 at i586

and what's available 'out there',

	/root# smart info MozillaThunderbird
		...
		Name: MozillaThunderbird
		 Version: 1.99.1-44.1 at i586
		 Priority: 17
		 ...
		 Channels: Latest mozilla.org packages @ SuSE
		
		
		Name: MozillaThunderbird
		 Version: 1.99.1-44.1 at i586
		 Priority: 5
		 ...
		 Channels: RPM System
		
		Name: MozillaThunderbird
		 Version: 1.5.0.8-3 at i586
		 Priority: 12
		 ...
		 Channels: SUSE 10.2 OpenSource Repository
		
		Name: MozillaThunderbird
		 Version: 1.5.0.9-0.1 at i586
		 Priority: 13
		 ...
		 Channels: SUSE 10.2 Online Updates
		 ...


it seems to me that smart should NOT be trying to 'upgrade' my
MozillaThunderbird anyway, as what's _installed_ is (a) the latest
available version and, (b) in the highest priority repo anyway.

any clarification would be appreciated.

thanks!