address checks updated

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

@@ -98,8 +98,7 @@ class ContractDropdownUI {
   enableAtAddress (enable) {
     if (enable) {
       const address = this.atAddressButtonInput.value
-      if (!address || !ethJSUtil.isValidAddress(address) ||
+      if (!address || !ethJSUtil.isValidChecksumAddress(address)) return
-      (/[a-f]/.test(address) && /[A-F]/.test(address) && !ethJSUtil.isValidChecksumAddress(address))) return
       this.atAddress.removeAttribute('disabled')
       this.atAddress.setAttribute('title', 'Interact with the given contract.')
     } else {

apps/remix-ide/src/app/tabs/runTab/model/dropdownlogic.js

@@ -43,12 +43,6 @@ class DropdownLogic {
   }
 
   loadContractFromAddress (address, confirmCb, cb) {
-    if (!ethJSUtil.isValidAddress(address)) {
-      return cb('Invalid address.')
-    }
-    if (/[a-f]/.test(address) && /[A-F]/.test(address) && !ethJSUtil.isValidChecksumAddress(address)) {
-      return cb('Invalid checksum address.')
-    }
     if (/.(.abi)$/.exec(this.config.get('currentFile'))) {
       confirmCb(() => {
         var abi