add SearchableDropdown styles

README.md

@@ -4,7 +4,7 @@ silverstripe-quickaddnew
 What is it?
 --------
 
-A decorator for form fields that manage object relationships, to allow adding a new object on the fly through a dialog window. It can handle `has_one`,`has_many` or `many_many` relationships. At the moment it has been tested / works on `DropdownField`, `ListboxField` and `CheckboxSetField`. It works both in the CMS and in the frontend.
+A decorator for form fields that manage object relationships, to allow adding a new object on the fly through a dialog window. It can handle `has_one`,`has_many` or `many_many` relationships. At the moment it has been tested / works on `DropdownField` (and `SearchableDropdownField`), `ListboxField` and `CheckboxSetField`. It works both in the CMS and in the frontend.
 
 ![screenshot](screenshot.png)
 

client/css/quickaddnew.css

@@ -3,6 +3,12 @@
     font-size: 0;
 }
 
+.cms .quickaddnew-field .ss-searchable-dropdown-field {
+    display: inline-block;
+    width: 437px;
+}
+
+.cms .quickaddnew-field .ss-searchable-dropdown-field,
 .cms .quickaddnew-field .chzn-container,
 .cms .quickaddnew-field .chosen-container {
     max-width: min(437px, 60vw);