Problem with textboxes

Very often (nearly always) it is impossible to enter text in textboxes.

I need this most often when I want to donate to my clan, but it also occurs in market textboxes, so I expect it to be a general problem.

So, I want to donate platinum, click on the corresponding textbox, but I cannot enter anything.

Not even the input cursor is visible.

Fortunately there is a workaround: if I refresh the browser it does work. Always.

But after some time, or after some actions, it becomes impossible again.

This is probably a browser issue: I use IE11.

Nevertheless it seems to be a game bug, since many other browser games use textboxes and they cause no problem.