diff --git a/windows/init.cpp b/windows/init.cpp
index 24831143..89d3837a 100644
--- a/windows/init.cpp
+++ b/windows/init.cpp
@@ -6,6 +6,7 @@ HINSTANCE hInstance;
 int nCmdShow;
 
 HFONT hMessageFont;
+uiWindowsSizing messageFontSizing;
 
 // LONGTERM needed?
 HBRUSH hollowBrush;
@@ -95,6 +96,11 @@ const char *uiInit(uiInitOptions *o)
 	if (hMessageFont == NULL)
 		return ieLastErr("loading default messagebox font; this is the default UI font");
 
+	// Initialize to zero to means that the values are unknown.
+	messageFontSizing.BaseX = 0;
+	messageFontSizing.BaseY = 0;
+	messageFontSizing.InternalLeading = 0;
+
 	if (initContainer(hDefaultIcon, hDefaultCursor) == 0)
 		return ieLastErr("initializing uiWindowsMakeContainer() window class");
 
diff --git a/windows/sizing.cpp b/windows/sizing.cpp
index 33cc00b9..df5661d7 100644
--- a/windows/sizing.cpp
+++ b/windows/sizing.cpp
@@ -34,7 +34,10 @@ void getSizing(HWND hwnd, uiWindowsSizing *sizing, HFONT font)
 
 void uiWindowsGetSizing(HWND hwnd, uiWindowsSizing *sizing)
 {
-	return getSizing(hwnd, sizing, hMessageFont);
+	if (messageFontSizing.BaseX == 0) {
+		getSizing(hwnd, &messageFontSizing, hMessageFont);
+	}
+	*sizing = messageFontSizing;
 }
 
 #define dlgUnitsToX(dlg, baseX) MulDiv((dlg), (baseX), 4)
diff --git a/windows/uipriv_windows.hpp b/windows/uipriv_windows.hpp
index 77982322..22cdfd56 100644
--- a/windows/uipriv_windows.hpp
+++ b/windows/uipriv_windows.hpp
@@ -86,6 +86,8 @@ extern void setWindowText(HWND hwnd, WCHAR *wtext);
 extern HINSTANCE hInstance;
 extern int nCmdShow;
 extern HFONT hMessageFont;
+// keep memory of text metric values given in getSizing in sizing.cpp
+extern uiWindowsSizing messageFontSizing;
 extern HBRUSH hollowBrush;
 extern uiInitOptions options;