Unsquared buildings in JOSM

I have seen somewhere that it is possible to search for unsquared buidings in JOSM, but I don´t remember how to do it. Can anyone tell me
an efficient way to search and correct unsquared buildings?

Topic solved, I hope.

After pressing cmd F use search string: building inview nodes:4- will result in finding buildings that you square by pressing Q.

Further reading: http://www.missingmaps.org/assets/downloads/MissingMaps_validation_josm_en.pdf

Thanks for sharing!