PSD files/layers pixels extended horizontally and vertically

[carolh76112497]

Sometimes, when I save and reopen a PSD file, the edges seem to expand either horizontally or vertically. I can usually select the pixels on that layer, inverse, and delete to get rid of extra pixels. If I have a lot of layers, it is time-consuming. What is this phenomenon called? How to prevent or fix it? Thanks

[c.pfaffenbichler]

Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Options Bar, …) visible?