diff --git a/src/states_screens/dialogs/gp_info_dialog.cpp b/src/states_screens/dialogs/gp_info_dialog.cpp
index 2f683c874..36fc61646 100644
--- a/src/states_screens/dialogs/gp_info_dialog.cpp
+++ b/src/states_screens/dialogs/gp_info_dialog.cpp
@@ -44,8 +44,11 @@ using GUIEngine::PROP_ID;
 
 typedef GUIEngine::LabelWidget Label;
 
-GPInfoDialog::GPInfoDialog(const std::string& gp_ident) :
-    ModalDialog(PERCENT_WIDTH, PERCENT_HEIGHT)
+const float GPInfoDialog::PERCENT_WIDTH  = 0.8f;
+const float GPInfoDialog::PERCENT_HEIGHT = 0.7f;
+
+GPInfoDialog::GPInfoDialog(const std::string& gp_ident)
+            : ModalDialog(PERCENT_WIDTH, PERCENT_HEIGHT)
 {
     doInit();
     m_curr_time = 0.0f;
diff --git a/src/states_screens/dialogs/gp_info_dialog.hpp b/src/states_screens/dialogs/gp_info_dialog.hpp
index f29d3ad2e..d221d44d9 100644
--- a/src/states_screens/dialogs/gp_info_dialog.hpp
+++ b/src/states_screens/dialogs/gp_info_dialog.hpp
@@ -62,10 +62,11 @@ protected: // Necessary for RandomGPInfoDialog
     /** only used for track_screen.cpp */
     GPInfoDialog() : ModalDialog(PERCENT_WIDTH, PERCENT_HEIGHT) {}
 
-public:
-    static const float PERCENT_WIDTH  = 0.8f;
-    static const float PERCENT_HEIGHT = 0.7f;
+private:
+    static const float PERCENT_WIDTH;
+    static const float PERCENT_HEIGHT;
 
+public:
     GPInfoDialog(const std::string& gpIdent);
     /** Places the focus back on the selected GP, in the case that the dialog
      * was cancelled and we're returning to the track selection screen */