I realized that if you switch off crop tool in the tool tab and click on the crop tool on top there are no guides displayed for full picture. This mean that you need to use mouse to crop the image.
If you have crop tool to on then you get the guides and you can easily crop in on one or two edges.
For me it would be great to have the guides always, even if crop tool is off because if I apply crop with top button it anyhow need to be switched on to be effective!
p.s.: All my other RAW converter/editors do show the guides always, therefore I am always confused with PL3.