diff --git a/frontend/pages/DefinitionList/components/DefinitionGraph/DefinitionGraph.tsx b/frontend/pages/DefinitionList/components/DefinitionGraph/DefinitionGraph.tsx
index 70dd95e..1337613 100644
--- a/frontend/pages/DefinitionList/components/DefinitionGraph/DefinitionGraph.tsx
+++ b/frontend/pages/DefinitionList/components/DefinitionGraph/DefinitionGraph.tsx
@@ -67,6 +67,7 @@ const WrapperSection = styled(Section)`
   flex-direction: column;
   height: inherit;
   flex-grow: 1;
+  width: 1px; /* flex width */
 `
 
 const FixedHeightHeading = styled(Heading)`
diff --git a/frontend/pages/DefinitionList/components/DefinitionSources/DefinitionSources.tsx b/frontend/pages/DefinitionList/components/DefinitionSources/DefinitionSources.tsx
index 230870e..36d4b89 100644
--- a/frontend/pages/DefinitionList/components/DefinitionSources/DefinitionSources.tsx
+++ b/frontend/pages/DefinitionList/components/DefinitionSources/DefinitionSources.tsx
@@ -159,6 +159,7 @@ const WrapperAside = styled(Aside)`
   padding: 0;
   height: inherit;
   overflow-y: scroll;
+  max-width: 400px;
 
   &&& {
     margin-top: 0;