Where did "Open in Safari" go? Suddenly, the option to open in Safari is missing from my share menu. It's not even listed in the "More" options menu. The only unusual thing I've done recently is to install iCloud for Windows on my laptop at work. It never did fully install, however, so I'm not sure how that could affect anything as I sync to iTunes on a MacBook Air. 

This is apparent in apps that use the horizontal icon-based share menu—e.g. Tweetbot or ABC News—the Safari option is gone. The share menu is different in other apps like Twitter or Facebook (where it's a vertical text list) and "open in Safari" is still an option in those.

Is anyone else having this problem? I've tried Googling this with no success. I've also cleared all Safari data and tried a reset with no luck. 

What am I missing? I'm on an iPhone 6 running the latest iOS 8.3.
One of the recent version update changelogs for Tweetbot states they made a change to the share sheet, which may in turn have caused a bug that is preventing Safari from showing up. This would best be reported to the developer of the app.

In iOS 8.x, a developer basically advertises "I have this type of data to be shared, what apps can share it?" The system responds with a list of apps that are capable of receiving that type of data. (Types can include text, a web URL, images, and so forth.) Depending on what type of data Tweetbot is advertising, it may not be compatible with what Safari says it can receive - Tweetbot might be advertising the URL in plain text format, whereas Safari might only be able to receive the URL specifically formatted as a URL.