From the Dash feature documentation: Hold the “ctrl” on the keyboard while dragging the right border of the PDF to create a grey margin of your desired width. This will function as a “freeform canvas” connected to the PDF that allows you to place documents such as annotations."
Ctl-left-click-drag resizes the PDF created by dropping a website on to Dash and does not drag out the grey margin. Ctl-left-click-drag on an imported PDF does create the grey margin.
From the Dash feature documentation: Hold the “ctrl” on the keyboard while dragging the right border of the PDF to create a grey margin of your desired width. This will function as a “freeform canvas” connected to the PDF that allows you to place documents such as annotations."
Ctl-left-click-drag resizes the PDF created by dropping a website on to Dash and does not drag out the grey margin. Ctl-left-click-drag on an imported PDF does create the grey margin.