simplify condition to show flatten button

libs/remix-ui/solidity-compiler/src/lib/contract-selection.tsx

@@ -254,7 +254,9 @@ export const ContractSelection = (props: ContractSelectionProps) => {
             </select>
           </div>
           <article className="mt-2 pb-0">
-            {showFlattener && <CustomTooltip
+            {api.getCompilationResult().data.sources[api.currentFile]
+              .ast && api.getCompilationResult().data.sources[api.currentFile]
+              .ast.nodes.some(x => x.nodeType === 'ImportDirective') ? <CustomTooltip
               placement="right-start"
               tooltipId="flattenContractTooltip"
               tooltipClasses="text-nowrap"
@@ -263,7 +265,7 @@ export const ContractSelection = (props: ContractSelectionProps) => {
               <button id="contractFlattener" onClick={flattenContract} className="btn btn-secondary btn-block mt-2">
                 <FormattedMessage id='solidity.flattenLabel' /> {api.currentFile}
               </button>
-            </CustomTooltip>
+            </CustomTooltip> : null
             }
             <CustomTooltip
               placement="right-start"