Fix positioning with loading/dropdown icon

RELEASE-NOTES.md

@@ -10,6 +10,8 @@
 
 **Bugs**
 - **Dropdown** - Fixed issue where using `down` key to re-open dropdown when using `search selection dropdown` would start at the top element instead of jumping to selected element
+- **Dropdown** - Fix dropdown arrow being slightly off center due to em calculation being incorrect due to differences in relative em
+- **Dropdown** - Fix `loading dropdown` icon position being slightly offset
 - **Sidebar** - Removed use of `ios` browser detection, and use of `-webkit-overflow-scrolling: touch;`. iOS no longer has sizing issues when displaying sidebar content in latest iOS.
 - **Search** - Fixed issue where `searchDelay` could cause results to appear after search had lost focus.
 - **Sticky** - Fix issue where sticky would cause page to shift when `context` height was determined by sticky's height in `position: static;`  #3430

src/definitions/modules/dropdown.less

@@ -769,7 +769,9 @@ select.ui.dropdown {
 
 .ui.loading.dropdown > i.icon {
   height: @relative14px !important;
-  padding: @relative16px @relative15px !important;
+}
+.ui.loading.selection.dropdown > i.icon {
+  padding: @relative21px @relative18px !important;
 }
 .ui.loading.dropdown > i.icon:before {
   position: absolute;

src/themes/default/modules/dropdown.variables

@@ -159,7 +159,7 @@
 @selectionIconZIndex: 3;
 @selectionIconHitbox: @selectionVerticalPadding;
 @selectionIconMargin: -@selectionIconHitbox;
-@selectionIconPadding: @selectionIconHitbox;
+@selectionIconPadding: @selectionIconHitbox / @dropdownIconSize;
 @selectionIconTransition: opacity @defaultDuration @defaultEasing;
 
 @selectionMenuBorderRadius: 0em 0em @borderRadius @borderRadius;