The display code will scroll any line, but scrolling of the top line is disabled as too many modes caused it to scroll when it was not desired.

If you want to try it just remove the check for $l == 0:

--- Slim/Display/Graphics.pm    (revision 24920)
+++ Slim/Display/Graphics.pm    (working copy)
@@ -385,7 +385,7 @@
                                        $sc->{scrolline} = undef;
                                }
 
-                       } elsif (!$scroll || $l == 0 || ($sc->{scroll} && $sc->{scrollline} != $l) || ($s2periodic && $screen1) ) {
+                       } elsif (!$scroll || ($sc->{scroll} && $sc->{scrollline} != $l) || ($s2periodic && $screen1) ) {
                                # scrolling not enabled, line 0 or already scrolling for another line - truncate line
                                if (!$sc->{linereverse}[$l]) {
                                        $bits |= substr($sc->{linebits}[$l], 0, $sc->{overlaystart}[$l]). $sc->{overlaybits}[$l];

To scroll the top line in preference to other lines reverse the order of the for loop above this (scrolling more than one line at once is not supported)

Andy - what example message would cause this issue?

Punting 7.4 bugs to 8.0

Adrian, andy notes that we don't want to enable scrolling of the top line anywhere.

I agree - if we scroll the top line there would be many places to fix to avoid it scrolling all the time (the reason its disabled, but wanted to point out the code handles it should we want to..)

I think the best solution is to move the problem error messages to the bottom line.  This needs a per error message fix though - i.e. the place creating the showBriefly needs its code updated to use the lower line.