The PlaceHoldersFor Login Do not show!

Hi, I really like this plugin, thing is that I set this widget, but the placeholders for user and pass do not show in my site: http://tienda.ryp.com.ve/tienda/

It is in spanish and it says “Identificación” for the title (left sidebar). The Placeholders are being hidden.

Now after working around it I added a link for login because I am using a modal login form, and I want to keep the plugin as it is, I mean placeholders hidden, but I don’t know why this is happenning in my site, maybe a css problem with my template?

In a nutshell, I want to have the control to hide an show those placeholders because this was a “good problem” but I can’t do it when needed. How could I do that when needed? Which code to use?

Thanks in advance.

https://wordpress.org/plugins/sidebar-login/