I've recently encountered an issue in Sitecore 8.2
After deleting the component in content editor. I tried navigating in page editor and clicked the DELETED component.
Now this is where the issue occurs. The options that are usually displayed in page editor are now gone, and after clicking the other components, they all behave the same way.
If I don't click the component that was deleted, then the other components behave normally. This didn't happen to me when I was using Sitecire 7.1 but now that I've upgraded to 8.2 I've recently encountered this issue.
What are the areas I can check? Is this issue known in Sitecore 8?
My recommendations to authors, regardless of version, is to always remove a component from presentation details before deleting any datasource in the Content Editor.
In fact, unless you made a drastic layout mistake, in most cases you should probably not delete the datasource at all.
As of Sitecore 8 editing now has versioned presentation details (Final Renderings). When removing a component from a page in Sitecore 8, you are editing a new version of the page. That new version will no longer have the component displayed. However, all previous versions will still have the component referenced. If you happened to roll back to a previous version, you would need that component. Unless you are removing from ALL versions (or from the shared layout) you probably shouldn't be removing the datasource.