It seems the need for hacks has not gone away with the move to cloud, but you do have to be more careful, as I have already found out Salesforce can break your custom code at will.
So that being true one of the things that SalesForce does not seem to have that every other framework does is a simple an powerful “hide when”, IMHO this feature should be present in every line button and object on every page and most platforms do,
It is the most requested feature for customisation that I have come across, and this is the hack that I use for read mode documents or forms (which strangely is where the request is most often made) (and yes it is a hack)
Lets break it down
We have to do a wait loop that keeps looking for the object till it finds it (then stops), because SalesForce adds button objects in after the page loads so they wont be there when it first opens
So we put this code into a Page
This insert that page into the layout Object layout we want it to effect.
that would normally give a big white space where the inserted form lives, so we make the page a 1% by 1px block
And that’s it, just save the layout, the button/”what ever” will hide when the page loads, a hack but a simple reliable hack
Now as always “hide when” is not security, remember to make sure that you don’t leave functions exposed and think this kind of thing covers you.