boolean isInstalled =/**...**/
Button appBtn = new Button(myComp, SWT.CHECK);
appBtn.setText("Upload to Server");
appBtn.setEnabled(isInstalled);
final ControlDecoration dec = new ControlDecoration(appBtn, SWT.TOP | SWT.RIGHT);
dec.setImage(PlatformUI.getWorkbench().getSharedImages().getImage(ISharedImages.IMG_DEC_FIELD_WARNING));
dec.setDescriptionText("Upload to Server feature is not available on the current plan");
dec.show();