Grasshopper Component Placeholders NOT working

Hi,

I am using Rhino 7 and Grasshopper. After I open a gh file with unrecognized objects in it and failed to install the missing plug-ins, I could not see the placeholders at where it should be on the canvas.

I am wondering how to make sure the ‘placeholder’ work.
Should I go to somewhere to ‘turn-on’ this feature? Does it follow some mechanism that I should know?

Rhino - Grasshopper Component Placeholders (rhino3d.com)

Hi -

Please run the Rhino SystemInfo command and copy-paste the result here.
-wim

There’s nothing you can do to enable, disable or change the way placeholders work. When confronted with an unknown object in the file, a placeholder will be added, but if it’s not a kind of known object (like a component or a standard parameter) then it’s unclear even how and where to draw the placeholder box.

Are the missing objects regular components?