Sliding objects up and left to remove unused space is set by default when creating a label layout. However, if the field on the left is a calculated field and the fields to the right are regular text fields, sliding will not occur.
For example, if you are making address labels and want the comma to be right after the name of the City, using a calculation and concatenating would do it. But the State and Zip Code fields will no longer slide left, eliminating the blank space.
The only workaround is to combine the whole row of fields in the calculation.
For example, a single calculation to concatenate these fields including a comma might be:
CityStateZip (calculation, text result)= 'City'&" , "&'State'&" "&'Zip'
Or the CONCAT function could be used:
CityStateZip (calculation, text result)= CONCAT('City',", ",'State'," ",'Zip')