If you need to edit a component which is correctly placed in your scene and find a difficult time to get to that component to edit it... just open component window, drag a copy of the component in open space and edit that copy, then delete. All the changes will affect the correctly placed component.
Also, if some plugins don't work, do the same operation above, but before editing scale the component to edit upwards by 10 or 100. Sketchup works better on bigger scales, but the changes you make in component will affect the non scaled component in your scene