+1, maybe showing them as grayed out / inactive. At least this way the user could see that it is already included.

I can make it look like below but I still need a hint on styling the text (grey out) inside the dialog because the underlying class responsible for the packages list is FilteredList.java which intern not using SWT label but a custom one.

Empty package image used for this may look inappropriate ? then it can be reverted to package image.

@lathapatil thanks for working on this, this looks fine to me, just a space between version and the text would be good.
Also it would be nice to have a checkbox (enabled by default) that reads "Show already imported packages"

@lathapatil thanks for working on this, this looks fine to me, just a space between version and the text would be good. Also it would be nice to have a checkbox (enabled by default) that reads "Show already imported packages"

Thanks for the quick feedback .

does it make sense to disable 'ADD' button during multi-selection if one of the selection is already imported ?

If this is not ok.. we can enable 'ADD' button even though one of the selection is already imported and can handle the addition of packages at backend

Should this behavior be applied for "Required plug-ins" and "Exported Packages" as well?

I think the button should only be disabled if ALL packages are already imported.

Should this behavior be applied for "Required plug-ins" and "Exported Packages" as well?

Yes that would be good.