Element keys set with Reacton .key(...) are not recognized by the ipyvuetify transition group

[egormkn]

Hello!
I'm not sure if this issue should be opened in reacton or ipyvuetify repository.
When I try to use Vuetify transition groups, I get an error in browser console saying:
[Vue warn]: <transition-group> children must be keyed: <v-dialog>

However I used a key method on reacton elements inside the group:

with rv.FadeTransition(group=True):
    if figures.raw_measurements:
        MplFigure(*figures.raw_measurements).key("raw_measurements")
    if figures.field_accuracy:
        MplFigure(*figures.field_accuracy).key("field_accuracy")
    if figures.calibration_moment:
        MplFigure(*figures.calibration_moment).key("calibration_moment")

(MplFigure here is a @reacton.component with rv.Dialog as the root element.)
Should the same keys be used by Vue in browser?