After upgrade, My freeze grid columns with blank header become like this
The test case is on https://trial.tryfoexnow.com/ords/f?p=102:3:6629201203904::NO, click Status to reproduce
I don't have this issue until upgrade to 3.0.1.
This is a behaviour change between Ext JS 4.x and Ext JS 6.x.
In the next hotfix for 3.0.1, we will automatically add an NVL on the heading text so you don't need to specify this.
To resolve this can you please add " " as the heading text.