This is the default mode and should be selected at all times except during stream drawing. When in this mode, if you click with the mouse on an item on your layout, the item becomes selected (while anything else that might have previously been shown as selected, becomes un-selected). If you want to keep adding items to the selected set, hold down the Ctrl key while you click. You can also select several items at once by clicking on an empty area of the flowsheet, and dragging a large enough rectangle the encloses all the items that you wish to select.
Button
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