diff --git a/src/frontends/xforms/FormPreferences.C b/src/frontends/xforms/FormPreferences.C
index 9fc3676639..4bb1d2c4f1 100644
--- a/src/frontends/xforms/FormPreferences.C
+++ b/src/frontends/xforms/FormPreferences.C
@@ -35,6 +35,7 @@
 #include "funcrequest.h"
 #include "author.h"
 
+#include "support/lstrings.h"
 #include "support/lyxfunctional.h"
 #include "support/lyxmanip.h"
 #include "support/tostr.h"
diff --git a/src/frontends/xforms/FormSendto.C b/src/frontends/xforms/FormSendto.C
index 766aaa7ae4..ac97db71dc 100644
--- a/src/frontends/xforms/FormSendto.C
+++ b/src/frontends/xforms/FormSendto.C
@@ -20,6 +20,7 @@
 #include "format.h"
 #include "gettext.h"
 #include "lyx_forms.h"
+#include "support/lstrings.h"
 
 using std::vector;
 
diff --git a/src/frontends/xforms/xformsImage.C b/src/frontends/xforms/xformsImage.C
index 5956906cb8..39feb72df7 100644
--- a/src/frontends/xforms/xformsImage.C
+++ b/src/frontends/xforms/xformsImage.C
@@ -16,6 +16,7 @@
 #include "format.h"
 #include "debug.h"
 #include "support/LAssert.h"
+#include "support/lstrings.h"
 #include "support/lyxfunctional.h"  // compare_memfun
 
 #include "lyx_forms.h"