Can't open more than one document at a time

I have to open a few text documents. No matter of they are three or six, sometimes it will open but most of times, they won't. Also, Pages won't start after jumping for a while in the Dock.

If you open the documents from the Open menu it will work but the Dock icon is buggy.

There is no way to fix this as this may be a bug that sometimes happens and other times does not…

But thanks for reading.