Wireshark allocates space to the 'Packet List Window' according to the space requirement of the last opened capture file.
This issue was migrated from bug 1205 in our old bug tracker.
Original bug information:
Reporter: Deapesh Misra
Status: RESOLVED FIXED
Product: Wireshark
Component: GTK+ UI
OS: Windows XP
Platform: x86
Version: 0.99.3