diff --git a/include/wx/vscroll.h b/include/wx/vscroll.h
index 4edcfddc24..fdaf961e5f 100644
--- a/include/wx/vscroll.h
+++ b/include/wx/vscroll.h
@@ -623,8 +623,7 @@ protected:
     // OnGetLineHeight instead (backwards compatible name)
     // note that we don't need to forward OnGetUnitSize() as it is already
     // forwarded to OnGetRowHeight() in wxVarVScrollHelper
-    virtual wxCoord OnGetRowHeight(size_t n) const
-        { return OnGetLineHeight(n); }
+    virtual wxCoord OnGetRowHeight(size_t n) const;
 
     // this function doesn't have to be overridden but it may be useful to do
     // it if calculating the lines heights is a relatively expensive operation
@@ -644,8 +643,7 @@ protected:
 
     // forwards the calls from base class pure virtual function to pure virtual
     // OnGetLinesHint instead (backwards compatible name)
-    void OnGetRowsHeightHint(size_t rowMin, size_t rowMax) const
-        { OnGetLinesHint(rowMin, rowMax); }
+    void OnGetRowsHeightHint(size_t rowMin, size_t rowMax) const;
 };
 
 #else // !WXWIN_COMPATIBILITY_2_8
diff --git a/src/generic/vscroll.cpp b/src/generic/vscroll.cpp
index 248ea31c66..530417aca3 100644
--- a/src/generic/vscroll.cpp
+++ b/src/generic/vscroll.cpp
@@ -963,7 +963,20 @@ wxCoord wxVarVScrollLegacyAdaptor::OnGetLineHeight(size_t WXUNUSED(n)) const
     return -1;
 }
 
-void wxVarVScrollLegacyAdaptor::OnGetLinesHint( size_t WXUNUSED(lineMin), size_t WXUNUSED(lineMax)) const
-{ }
+void wxVarVScrollLegacyAdaptor::OnGetLinesHint(size_t WXUNUSED(lineMin),
+                                               size_t WXUNUSED(lineMax)) const
+{
+}
 
-#endif
+wxCoord wxVarVScrollLegacyAdaptor::OnGetRowHeight(size_t n) const
+{
+    return OnGetLineHeight(n);
+}
+
+void wxVarVScrollLegacyAdaptor::OnGetRowsHeightHint(size_t rowMin,
+                                                    size_t rowMax) const
+{
+    OnGetLinesHint(rowMin, rowMax);
+}
+
+#endif // WXWIN_COMPATIBILITY_2_8