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To select multiple items, you repeatedly select single items using their checkboxes until all your items are selected (toggle selection). Alternatively, use a rubber band rectangle when using a mouse to select the items (object selection). Note that in the latter case, the checkboxes of all selected items are also checked as soon as you release the mouse button. A previously selected group of items is first deselected before the newly defined group becomes selected by a rubber band.
Any visible and enabled view for item details will refresh immediately and show additional details on the set of selected items (e.g. summary of all sizes, number of selected items, etc.).
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