Administration: Improve dashboard widgets border styles.

This changeset fixes a CSS glitch on dashboard widgets bottom border when they are collapsed.

Follow-up to [61646].

Reviewed by westonruter.
Merges [62206] to the 7.0 branch.

Props pratik-jain, audrasjb, ankitkumarshah.
Fixes #65017.
See #64549.



git-svn-id: https://develop.svn.wordpress.org/branches/7.0@62214 602fd350-edb4-49c9-b593-d223f7449a82

Author: audrasjb

src/wp-admin/css/common.css

@@ -2281,7 +2281,7 @@ html.wp-toolbar {
 	line-height: 1;
 }
 
-.postbox.closed {
+.postbox.closed .postbox-header {
 	border-bottom: 0;
 }