created an attachment (id=169441)
screenshot

description:
live preview is empty after changing cube and correct the expression in chart builder

build number: 
2.6.0.v20100521-0630

steps to reproduce:
1, new a chart binding with cube which has country dimension
2, new another cube without country dimension
3, edit the chart and binding to cube2
4, correct the expression to a existing dimension and check the live preview in chart builder

expected result:
the live preview is correct after changing cube and correcting binding

actual result:
the live preview is empty
i don't see this issue.
could you provide the report?
can't reproduce.
user must make sure all expressions are valid in new data cube binding.
verified in 2.6.0.v20100525-0630 build