  CR Boo is one of the brightest and most famous AM CVn stars showing dwarf
nova-type outbursts. Previous studies showed different modes of outbursts in
this object ranging from the one equivalent to a hydrogen-rich ER UMa star or
WZ Sge star to a low-amplitude oscillating state. We for the first time
identified a bona fide standstill in this object in 2022 and we consider that
CR Boo is a helium analog of Z Cam stars in addition to its SU UMa/ER UMa-type
classification. The standstill lasted for ~60 d with variations typically less
than 0.2 mag and ended with fading. This standstill was not preceded by a
superoutburst and was different from a post-superoutburst phenomenon. The
brightness after the standstill was similar to those after superoutbursts and
the standstill appears to have acted like a superoutburst in effectively
accreting the disk mass. The existence of a standstill in an AM CVn star be a
challenge to theories of a helium disk or a degenerate secondary to explain how
such a state could be maintained.
