This thread is not for general Ext 4 bugs! It is for collecting Ext 3 to 4 migration discussion and issues in one place, including:
  • Issues in the Ext 4 Overview Guide
  • Issues in the Ext 3 to 4 Migration Guide
  • Issues or missing overrides in the Ext 3 compatibility file
  • Discussion about migrating specific code from 3 to 4

Migration Resources:

If you find anything while migrating that is not covered in any of the above, please post it here.