diff --git a/src/network/network_chat_gui.cpp b/src/network/network_chat_gui.cpp
index 57c4ac6c3e..ce6064e8c1 100644
--- a/src/network/network_chat_gui.cpp
+++ b/src/network/network_chat_gui.cpp
@@ -112,16 +112,22 @@ void CDECL NetworkAddChatMessage(TextColour colour, uint8 duration, const char *
 	_chatmessage_dirty = true;
 }
 
+/** Initialize all font-dependent chat box sizes. */
+void NetworkReInitChatBoxSize()
+{
+	_chatmsg_box.y       = 3 * FONT_HEIGHT_NORMAL;
+	_chatmsg_box.height  = MAX_CHAT_MESSAGES * (FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING) + 2;
+	_chatmessage_backup  = ReallocT(_chatmessage_backup, _chatmsg_box.width * _chatmsg_box.height * BlitterFactoryBase::GetCurrentBlitter()->GetBytesPerPixel());
+}
+
 void NetworkInitChatMessage()
 {
 	MAX_CHAT_MESSAGES    = _settings_client.gui.network_chat_box_height;
 
 	_chatmsg_list        = ReallocT(_chatmsg_list, _settings_client.gui.network_chat_box_height);
 	_chatmsg_box.x       = 10;
-	_chatmsg_box.y       = 3 * FONT_HEIGHT_NORMAL;
 	_chatmsg_box.width   = _settings_client.gui.network_chat_box_width;
-	_chatmsg_box.height  = _settings_client.gui.network_chat_box_height * (FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING) + 2;
-	_chatmessage_backup  = ReallocT(_chatmessage_backup, _chatmsg_box.width * _chatmsg_box.height * BlitterFactoryBase::GetCurrentBlitter()->GetBytesPerPixel());
+	NetworkReInitChatBoxSize();
 	_chatmessage_visible = false;
 
 	for (uint i = 0; i < MAX_CHAT_MESSAGES; i++) {
diff --git a/src/window.cpp b/src/window.cpp
index 091528c11b..bc4f31ed14 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -2619,6 +2619,10 @@ void ReInitAllWindows()
 	FOR_ALL_WINDOWS_FROM_BACK(w) {
 		w->ReInit();
 	}
+#ifdef ENABLE_NETWORK
+	void NetworkReInitChatBoxSize();
+	NetworkReInitChatBoxSize();
+#endif
 
 	/* Make sure essential parts of all windows are visible */
 	RelocateAllWindows(_cur_resolution.width, _cur_resolution.height);