Truth be told...
I don't want to spoil the outrage about bad inve$tors and their cynical, selfish, greedy capitalism (cf. the latest AIDS pharmaceuticals outrage). But truth be told, many people who are working with Citrix products for many years (in my case since the year 1999 if memory serves) think that the company lost focus lately.
"XenApp is dead, go XenDesktop" in one year, followed by "No no, forget about this, we are now all doing XenMobile, you know, 'work is not a place' ?" followed by this year's "What we actually meant is that it's all about the app, you know, 'software defined workplaces', btw we are all so excited about XenApp now!"
Combine this with questionable acquisitions (AppDNA springs to mind), and problems matching old version features in new product releases, I can understand that an investor becomes nervous. Not that I think that selling off Netscaler would be a good idea. But it's too simplistic to make a scape-goat out of Elliot here.