auto checksuming address for atAddress

apps/remix-ide/src/app/tabs/runTab/contractDropdown.js

@@ -97,7 +97,10 @@ class ContractDropdownUI {
   enableAtAddress (enable) {
     if (enable) {
       const address = this.atAddressButtonInput.value
-      if (!address || !ethJSUtil.isValidChecksumAddress(address)) return
+      if (!address || !ethJSUtil.isValidAddress(address)) {
+        this.enableAtAddress(false)
+        return
+      }
       this.atAddress.removeAttribute('disabled')
       this.atAddress.setAttribute('title', 'Interact with the given contract.')
     } else {
@@ -387,7 +390,10 @@ class ContractDropdownUI {
   loadFromAddress () {
     this.event.trigger('clearInstance')
 
-    var address = this.atAddressButtonInput.value
+    let address = this.atAddressButtonInput.value
+    if (!ethJSUtil.isValidChecksumAddress(address)) {
+      address = ethJSUtil.toChecksumAddress(address)
+    }
     this.dropdownLogic.loadContractFromAddress(address,
       (cb) => {
         modalDialogCustom.confirm(null, 'Do you really want to interact with ' + address + ' using the current ABI definition?', cb)