Hi,
Editing using the WYSIWIG editor in campaign is somehow limited if you need to add content and components. There are plans to replace this editor in an upcoming release, but in the meantime I'd recommend using dreamweaver as it also offers WYSIWIG capabilities and works fine with Campaign.
This is my personal recommendation considering what you just described, but you can also try AEM if you have a working integration, or directly editing the HTML version by selecting the "Source" button when you are in Campaign's wysiwyg editor.
Let me know what you find more convenient, that will be good feedback for the team.
Stay tuned for the updates to come in the following months regarding this editor.
Florent