I'm using the Generic Views module for a frontend form for a dataobject. It's been working great for a while now. As soon as I installed the Event Calendar module, the search text is missing from the button on the form. It's now a just an orange square instead of an orange rectangle with the word "Search" on it.
I'm able to reproduce this on a couple of other sites, it's definitely the event calendar module that removes the text. I don't know enough about either module (only that I like their functionality) to know where to look for a solution.
There may be something in the Event Calendar Module CSS which is overriding the styling of the Generic Views. You might want to check the input or button styling in the Event Calendar Module and see whether there is anything that would replace/remove the text from the search button.