@telemarker A couple of weeks ago I came across this issue somewhere else and I finally figured out what caused it. For a long time, I thought it had to do with performance issues, but that’s not the case.
The reason is transitions: whenever the sticky element contains transitions, you will see this happen. In your case, you’ve put transitions on a number of elements, such as:
.main-container a {
-webkit-transition: all 250ms ease-in-out;
-moz-transition: all 250ms ease-in-out;
-ms-transition: all 250ms ease-in-out;
-o-transition: all 250ms ease-in-out;
transition: all 250ms ease-in-out;
cursor: pointer;
}
Because of this, when the sidebar becomes sticky, that transition actually kicks in: the sticky sidebar becomes visible, but it will take another 250ms before the “normal” sidebar will disappear. Hence, for this short period of time you will see your menu twice.
I’ll look into adding something general into the plugin that will avoid things like this, but for the time being, you could add this to your stylesheet:
.original, .original * {
transition: none !important;
}
@prti: Maybe this is also the case for your site, but I won’t be able to tell for sure without seeing it.