That is okay solution.

However, you could add your

.select.cke_dialog_ui_input_select

css to custom styles file and it would work fine as well.

Thanks for posting!

Take care :)

I am aware of that class.  However I can't easily add classes to ckeditor's dialogs as they are created deep in ckeditor's javascript.  There is a much quicker and global fix:

In the mdb.css, line 10721 we have:

select {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  display: none !important; }
  select.browser-default {
    display: block !important; }
  select:disabled {
    color: rgba(0, 0, 0, 0.3); }

Change it to:

select {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
display: none !important; }
select.browser-default {
display: block !important; }
select.cke_dialog_ui_input_select {
display: block !important; }
select:disabled {
color: rgba(0, 0, 0, 0.3); }

Adding the

select.cke_dialog_ui_input_select...

globally fixes this issue.