fix: revert workaround for #7

fix #68

If you're using MUI 3, you may see issue #7 happening again.  If so, you'll need to
investigate the issue with the authors of MUI/decide how to work around it yourself.

Author: jedwards1211

package.json

@@ -153,6 +153,7 @@
     "prop-types": "^15.7.2"
   },
   "peerDependencies": {
-    "react": "^15.0.0 || ^16.0.0 || ^17.0.0"
+    "react": "^15.0.0 || ^16.0.0 || ^17.0.0",
+    "@material-ui/core": "^4.0.0"
   }
 }

src/core.js

@@ -118,13 +118,6 @@ export function createPopupState({
         if (!parentPopupState.isOpen) return
         parentPopupState._setChildPopupState(popupState)
       }
-      if (
-        !disableAutoFocus &&
-        typeof document === 'object' &&
-        document.activeElement
-      ) {
-        document.activeElement.blur()
-      }
 
       const newState: $Shape<CoreState> = {
         isOpen: true,