Font diaplay problem after change the theme and the font size

I like dark theme , so I change the theme to Breeze Dark in “configure desktop” -> “WorkSpace theme” -> “look and feel”.
Besides, the default font size is small for me, so I make it larger.
Then the problem comes
After the change, some buttons in the windows become white and blank, and some fonts in the windows cannot be displayed properly.
Sorry for my poor English. Maybe these pictures can help me describe the problem better

http://imagezilla.net/show/CRV71om-problem1.png
http://imagezilla.net/show/WksbQbu-problem2.png

http://imagezilla.net/thumbs2/CRV71om-problem1_tn.png](http://imagezilla.net/show/CRV71om-problem1.png)
http://imagezilla.net/thumbs2/WksbQbu-problem2_tn.png](http://imagezilla.net/show/WksbQbu-problem2.png)

Could anybody give me some help?
Thanks in advance.