Tag selector UI tweaks

- Don't cut off bottom of tags on Windows
- Fix appearance of search bar on Windows/Linux
- Fix cancel button on Windows/Linux
- Don't cut off right-hand pane of bottom bar when narrowing pane

scss/components/_search.scss

@@ -1,21 +1,16 @@
 .search {
 	position: relative;
+	min-width: 40px;
 }
 
 .search input {
-	-moz-appearance: searchfield;
 	flex: 1 0;
 	min-width: 40px;
-	height: 24px;
 	padding-left: 4px;
 }
 
 .search .search-cancel-button {
-	background-image: url(chrome://global/skin/icons/searchfield-cancel.svg);
 	position: absolute;
-	width: 14px;
-	height: 14px;
-	top: 6px;
 	right: 6px;
 	cursor: default;
 }

scss/components/_tag-selector.scss

@@ -74,7 +74,7 @@
 	overflow: hidden;
 	text-overflow: ellipsis;
 	white-space: pre;
-	padding: 1px 4px 3px;
+	padding: 1px 4px 3px; // See also tag-list.jsx
 
 	&.colored {
 		font-weight: bold;