MTU CheckBox
In Version 3.08, when this box was ticked, a dialog box appeared. This has changed in Version 4. The checkbox now works in a more logical way. When you start MTUSpeed, it checks to see if the MTU values for all TCP keys detected are the same. If so, the box gets ticked automatically. If not the box remains unchecked.
If the box is checked and you press the "Change MTU" button the value entered is applied to ALL MTU keys in the dropdown list. If the box is unchecked, the "Change MTU" button ONLY applies to the MTU key displayed in the dropdown box.
Additionally, if the box is checked and you select MTU to "disable" on the Registry page, ALL the MTU's will be disabled.
In short, the MTU Checkbox now acts as a proper toggle. With it
unchecked your changes are ONLY applied to the TCP key displayed in the dropdown list. With it checked, any changes that can affect the
MTU value are applied to ALL TCP keys stored in the dropdown list.