There really needs to be a button for “clear all keyframes”, or at least a function to select multiple keyframes and delete them.
Anyway, there’s a dead keyframe on encapsulation “Rudolf” I can’t seem to remove. 
Your sushi3.sifz (28.9 KB)
Hi!
Maybe it is useful but I would work on other thing related to keyframes like remove a keyframe and keep the waypoints for example.
There are two keyframes on the composition and I can delete them without troubles. Go to Keyframe panel, select the keyframe and press the Delete (trash can icon) button.
Or, maybe are you confusing keyframe with waypoint?
(To delete any waypoint just ALT-clic on it)
wiki.synfig.org/wiki/Mouse_Shortcuts
-G
Yeah, I was confusing keyframes with waypoints. LOL Thanks.
And no, Alt-Click doesn’t work for me. 
Nor does Right-Click > Remove.
The only waypoint(s) at 14f can be deleted with ALT-clic here. To remove all them just select the top paste canvas layer and do ALT-left clic on it. I can delete it here.
-G
Doesn’t work. @_@ It simply moves the window. Could it by Compiz?
UPDATE: Changed the Compiz setting. It works now! 