cellGroups not completely removed when removing column?

Hello,

I have a Grid which looks like this http://screencast.com/t/qMkZdSg5iOf, where I can add and delete columns dinamically.

When I select delete column 1, I want all columns below the header 1 to be removed. In order to do that I'm using this in a loop:

grid.removeColumn(propertyId);

But when removing columns I get the following exception, thrown by Grid.sanityCheck():
java.lang.IllegalStateException: Not all merged cells were in a continuous range.

When debugging my code I see that this

grid.getHeaderRow(0).getRowState().cellGroups.keySet()

returns [[2, 3, 4], [5, 6, 7, 8]] before removing any columns, then, inside my loop, keys 5 and 6 are removed, but 7 and 8 are not. As I result I get the above exception..

I don't understand why some of the keys are being removed and others aren't.. Actually if I debug deeper, in the Grid.internalRemoveColumn(), inside this remove method: 

getState().columnOrder.remove(columnKeys.key(propertyId));

it seems that the keys do get removed..!

Any help is much appreciated.
Thalia

Did you ever figure this out?