[dwm] popup on a window in two tags : bug?

The background:

in config.h I have the rule:

{ "Mozilla-thunderbird-bin.*", "Mail", False}, \

when dwm is running I type the shortcut corresponding to :

{ MODKEY|ControlMask|ShiftMask, XK_apostrophe, toggletag, { .i = 4 } }, \

(I am with a french keyboard that why I use XK_apostrophe)

So my Thunderbird window is tagged with "Mail" and with the 4th tag. But when a
popup occured on this window and I am displaying only the 4th tag then I can't
see this popup and I must go to the tag "Mail" to respond to this popup.

Is there a way to display this kind of popup on all tags that handle the window
of Thunderbird?

This problem is probably the consequence of my static Rule defined in my
config.h; but is it the normal behaviour?

--
capitn