[BUG] Impossible to drag / reposition a tween keyframe elsewhere in the timeline

[nekohayo]

Testing out https://www.wickeditor.com/editor/ with Firefox on Fedora Linux, I've come with some "habits" or workflow expectations from my previous life doing Flash animations, so forgive me if what I'm requesting here is already implemented differently and I did not notice, but at first glance it seems like a case of "not implemented at all": we should be able to move keyframes (tweens) around in the timeline.

Currently, if I create a tween with an initial keyframe at the beginning of the timeline, expand the duration of that thing so that I can create another keyframe / tween frame later in the timeline (ex: at frame 10 while the extended area was going up to frame 20), I am unable to move that keyframe from position 10 to position 15 by attempting to drag it, no matter if I click-and-drag directly (in which case it it rather drags the whole area), or single-click the keyframe to attempt to select it first, or double-click it. None of that seems to work, and I would have expected it to as a "natural" way to move keyframes around for retiming animations.