the problem appears because the some component attributes - not generated for M2 to taglib.xml by CDK. So the IDE has no idea where to get them. E.g. for togglePanel - them should be available.
Is there will be some snapshot release for M2 that will fix it, or we will need to wait for M3 ?
Is the roadmap available for release dates of M3 and CR1 ?
We are actually planning out all the releases to Final now, and will be posting an update/blog soon. The milestone releases are roughly monthly. So expect M3 at the start of October.