Ocular-gatsby issues on the luma.gl site

[tsherif]

Mostly in IE/Edge, except for the first one.

Staged site: https://tsherif.github.io/luma.gl/

• Direct navigation to the following pages (among others) loads the wrong page (All browsers)
  • https://tsherif.github.io/luma.gl/docs/whats-new
  • https://tsherif.github.io/luma.gl/docs/upgrade-guide
  • https://tsherif.github.io/luma.gl/docs/get-started/examples
  • https://tsherif.github.io/luma.gl/docs/developer-guide/shadertools/shader-assembly
    (Seems like it's anything that's not the first item in a menu?)
• Header menu items off screen (Edge)
  
• Header position lags behind scroll (Edge/IE11)
• Menu items don't appear when a submenu first opens, but appear after you mouse over them (Edge/IE11)
  

[ibgreen]

@jckr

• The direct navigation issue seems quite important to fix as it affects all browsers.
• I have seen the disappearing menu items, e.g. when I mistype something in the toc.json (not quite sure what triggers it) might be worth adding more checks to that component to make it more robust?