There are a few usability problems with the resource picker. The resource picker is the view in Lessons typically accessed by clicking “Add Content”, then “Add Content Links”, and then “Or select existing files from Resources”.
If a user lands on the resource picker and decides to cancel this operation, there is no “Cancel” button immediately presented, like there was in Sakai 11. See CancelButton_Sakai11.png.
In case this omission might have been intentional, note that for subpages the links in the Lessons breadcrumb trail do not suffice for performing a cancel event. Those links force the user to navigate away from the page that the user was previously on.
The styling for the “Add” dropdown menus for each folder seems to be missing, given the appearance of list bullets. See CurrentStylingForAddDropdowns.png. Also, in order to open any of these dropdowns, the user must click the text for “Add” even though the mouse cursor does not indicate that this is a link. Clicking the dropdown image to the right does nothing. Once the dropdown is expanded, the result looks like CurrentStylingForAddDropdown_ExpandedMenu.png.
To fix this, I assume that the expected behavior that was evident in Sakai 10 and depicted in StylingForAddDropdownInSakai10.png would need to be transposed to Sakai 12 with the styling that can be found in Resources, depicted in ExpectedStylingForAddDrowpdown.png.