When I open a PDF from a file in Firefox, the file appears in a new browser window. When I try to click and drag the tab to another window, it just drags the PDF tab out of the window it was in and creates a new window, so the PDF tab won't go with the windows that already existed before the PDF was opened. The new window doesn't seem to have the same extensions I have installed on the other window, but it is also not an Private Window because that icon doesn't appear in the top right like it normally does. I am also signed into the same account on both windows.