Sticky bar ignoring z-index in Google Chrome

[acgimpy]

I added a navigation bar (ribbon style) to a website that I'm currently working on and used the jQuery Sticky Plugin to make it make it fixed to the top of the viewport when the user scrolls.It works perfectly in Firefox, but Chrome disregards the z-index of the sides of the ribbon as soon as the bar sticks. I have spent the last 7 hours googling for a solution to this. I've tried a range of different recommendations including un-nesting the bar and setting positions and z-index values manually for all elements, but to no avail. In fact, I ended up starting from scratch because I had only made it worse trying to fix it.Could anyone please tell me what I should change to fix the sides of the ribbon when scrolling in Chrome? THANKS!