Try the following:
File --> New/Restore --> Enter name for wallet --> Select 'Restore a wallet or import keys' and 'Standard Wallet' --> Copy & Paste the xpub key of the wallet you want to 'watch' --> Click OK
Should then load up the wallet which will be in Watch only mode as there is no private keys.
So instead of entering the seed for the wallet you enter the xpub key for the wallet.