1) As long as both windows have the same found set and sort order, You can use Select window to switch from one window to another and then use your variable in a go to record step to synch the second window's current record to match the first.
2) A simple script trigger combined with a global variable or field and a conditional format can do this.
Write a script with this line in it: Set Variable [$$CurrentRecord ; Value: Get ( RecordID ) ]
On the layout where you want this feature, use the OnRecordLoad script trigger to perform this script.
Last step: select the field or fields that make up this record you want to highlight and assign the following condtional format expression: $$CurrentRecord = Get ( RecordID ). Select an appropriate highlight color and the fields of the current record will automatically highlight on this layout.