Just by coincidence I now found out the exact trigger: when the a bin clip is already selected, then double clicking on the icon causes an edit clip name. It should instead cause an edit clip though. When the bin item isn't selected, then double clicking does start an edit clip.

In my view this is inconsistent behavior that may especially drive newcomers nuts, but also at least one old hand... ;)

i confirm that it is greyed out, but if you double click on it in the bin you are able to edit it. it would be nice to double click on the clip in the timeline and also have the edit dialog pop up.

There is maybe some confusion between functions.
"Edit Clip" is supposed to open clips in external applications, like gimp for images, audacity for audio.
"Clip Properties" displays the clip info but also allows you to change some settings, like length, color, aspect ratio.

Currently, editing title clips is triggered by the "Clip Properties" option in the context menu (as well as double click in bin).

Do you think it should be changed?

I have to admit that I would never expect "Clip Properties" to edit the title ... but then, you probably refer to the edit button inside the clip properties. Now that's a hassle when working with projects with several title clips. What about adding a "edit title clip", "edit color clip", and "edit image sequence clip" to the context menu?

The strange thing is that sometimes Kdenlive interprets the double click as to edit the title instead of to show the clip properties. I think we need to get a more consistent UI experience here.

Edit clip now works for titles, so this is fixed now, and I'm closing this report. Thank you Jean-Baptiste for fixing.