On the left side the package manager says:
Just below 'All' if there was 'Upgrades' it would save time when trying to 'find' the upgrades to see what they are rather then haveing to go through many pages and missing some.
At the top the 'buttons' say:
Reload Mark All Upgrades Apply
A 'button' that said 'Check All Upgrades' or 'Select All Upgrades' would also help.