I found a conflict with e-newsletter and another plugin - just and FYI -
plugin: Preserved HTML Editor Markup
Version 1.5 | By Marcus E. Pope, marcuspope
This is what would happen: When I would go in to create a newsletter - I can choose a template, adjust images, settings, color and send preview but if I click on Content - the sidebar shrinks to a size so small I cannot see the boxes or buttons and therefore cannot add content. I tried on Safari and Firefox - both do the same. I can grab the text box area corner and drag to expand it but it expands behind the preview area.