Time, Tempo, and Meter : Meter Events : Partial Measures
 
Partial Measures
As necessary, Pro Tools will create a partial measure to accommodate the inserted meter event. When a meter event is preceded by a partial measure, the meter event is displayed in italics in the Meter ruler.
Partial measures can also occur when pasting meter events to locations other than the first beat of a measure.
*To insert meter events while avoiding partial bars, use the Change Meter command in the Time Operations window. “Change Meter” on page 476.