How to modifiy dates of a task

Hi,

I am learning how Projeqtor works. I have search within the forum without results. So, I hope not asking an already treated subject.

I have created a project and then, an activity. The first dates fr the activity were may 5th. However, the meeting has been postpone on may 7th.
Although I modified the dates in the activity control panel, the activity remain scheduled on may 5 in the Gantt.

I don't find how to modify easily without deleting the activity and creating a new one.

Could someone help ?

Thanks in advance.
Sterwen