Yes, I'm aware of that but there is no 64-bit version of xulrunner that will work with 64-bit SWT at the current time of writing.
Thus you have two options on Windows:
Run with 32-bit and have all the visual page editor features.
Run with 64-bit and don't have the visual part of the page editor working - all the code completion,navigation etc. and in the source tab will continue to work.
I wish I had the magic wand to fix it but not something we've found a solution for.