Questions about the Polygon Selection Tool

Frequently, when I am using the polygon selection tool, my laptop registers a click as a double click and auto-completes the selection. This results in a messed up selection like the following:

Is there any way to fix these selections? I saw on the user manual the alt and shift keys can be used to modify my selections, but I couldn’t figure out how to use it. Is there any way to disable the double click auto-completion or to undo the last click? Sometimes it takes me several minutes (or several tries) to make one polygon, so it’s rather frustrating when it gets messed up.

Thank you all for the help!

Hi @ryansiu3,

you can use the selection brush to correct outlines as shown here:


You can find a more detailed information on how to use it in combination with SHIFT and ALT here:

Slides 64-67

I hope that helps!



A while ago I posted a suggestion to a similar problem, see:

I would also recommend to add the selections to the ROI Manager where you can reneable them, e.g., when you have to interrupt your work.

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Thank you so much, this definitely helps!

Thanks for this suggestion, I’ll try it out!

The latest ImageJ daily build (1.52r32) changes the double click interval from 500ms to 300ms, which should reduce the likelihood of errors like this. Also, if there are more than 25 points, you get a dialog asking if you want to complete the selection. Note that it may be possible to recover from errors like this by adding new points, which you do by shift clicking of existing points.

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Thank you for this information!