When selecting multiple ship modules in the designer and selecting "Hide Part", none of the selected parts are actually hid although the icon indicates that it has been activated and it works correctly when only a single components is selected
The function is often used when a custom ship model is used that does not support the looks and sizes of the default modules or if there are too many components on the ship and thus deform the looks of the ship (which kicks in around medium hull size). In these cases each component needs to be selected individually and must be clicked to be hidden or resized to minimal.
Please fix the function when multiple modules are selected or implement a way to hide all parts with a single click (if one or two of them needs to be visible the user can still select those individually and unhide them