I wanted to add oEmbed from CKEditor to the toolbar in IPS, but it had dependency issue.
So I installed in this order:
1. Lineutils
2. Widget
3. oEmbed

Now I cannot see any toolbar buttons in the toolbar. Only the separator line shows. Is there a way to manually remove these last edits. I dont want to reset because I have made some custom buttons before that I need.

Stig 

The same for me adding Enhanced Image (image2) plugin.

I'll leave it to someone else to guide you through fixing this.

But....did you install the 4.4.x versions of the plugins (they worked fine) or the 4.5.1/4.5.2 versions of the first 2 plugins (that gives me the above problem which I'm not surprised about, as the CKEditor version included with IPS4 at present is 4.4.7)