Fix problem with textarea background colour

Fixes #2772

themes/tiddlywiki/vanilla/base.tid

@@ -928,6 +928,7 @@ button.tc-untagged-label {
 .tc-tiddler-frame iframe.tc-edit-texteditor {
 	padding: 3px 3px 3px 3px;
 	border: 1px solid <<colour tiddler-editor-border>>;
+	background-color: <<colour tiddler-editor-background>>;
 	line-height: 1.3em;
 	-webkit-appearance: none;
 }
@@ -941,10 +942,6 @@ button.tc-untagged-label {
 	border: 1px solid <<colour alert-border>>;
 }
 
-.tc-tiddler-frame input.tc-edit-texteditor {
-	background-color: <<colour tiddler-editor-background>>;
-}
-
 canvas.tc-edit-bitmapeditor  {
 	border: 6px solid <<colour tiddler-editor-border-image>>;
 	cursor: crosshair;