[ES] Alt labels not displayed

Hello all,
I’m currently using Capella 1.3.1 and I have some unexpected difficulties to display labels on a ALT statement of an Exchange Scenario.
The Show hide view eventually indicate that the “label” is empty, but I was not able to find out where I can fill this.
When slowly double clicking (to edit the name as you would do for the name of a file), I can rename the Operand’s name. But still no success. Nothing gets displayed.
When I eventually underline the text, it adds a small line as a label, but without any text …
I checked most of option/parameters of the Style and Appearance tabs, changing colors, the “Hide label” option, label size. So far no success.
Anthything else in particular I could check to display those labels ?
Thanks in advance,
Regards,
Mathias

Did you use the “Guard” field in the Operands inside the ALT fragment?

It worked !
I was thinking it was only to provide a relation with a state machine. I should have tried it before anything else …
Thanks !