This question already has an answer here:
This happens quite often:
- Notice a question in the "related" pane that I have confirmed or know is a duplicate of this question
- Click on close → duplicate
- The duplicate is not on the list
- Right-click on the duplicate in the side bar and select "copy link address"
- Right-clicking outside the close dialog has hidden it
- Click on close → duplicate again
- Paste the duplicate's link to the input field
To make selecting duplicates from the side bar easier, I suggest that:
- Right-clicking shouldn't close the dialog which would remove steps 5-6 and
- Left-clicking should close the dialog only on mouseup instead of mousedown because doing it like this would be even more convenient.