Column alignment in a GroupSummaryView summary row in a doesn't work the same ways as the alignment of the non summary data.

This is visible on the LiveSummaryView demo for 2.1.1 and 2.2.0 beta and affects IE8, FF3 and Chrome.

Just make the cost estimate and rate columns small.

The normal columns truncate overflow data (when the data is wider than the column width), but the summary row does not.

This is caused by a missing style - "x-grid3-summary-table". This style is not in any included css file.

The fix is to add this class name to use the same style as x-grid3-row-table
Code:
.x-grid3 .x-grid3-row-table .x-grid3-summary-table {
  table-layout: fixed;
}
See the attached picture from the 2.2.0 Beta demo:
GXT220SumColAlignIssue.jpg