It should be the smae Scroll Bar bug in K-Meleon 74.
Since first version of K-Meleon 74 if the Gestures K-Meleon Plugin is enabled the Scroll Bar does not go up and down when you drag ir up and down.
I mentioned it in "Re: K-Meleon 74: bugs and deficiencies list" at
http://kmeleonbrowser.org/forum/read.php?1,125646,126096#msg-126096