Removed unnecessary space if the secondaryText argument to MsgBox***() is an empty string. This doesn't change much on Mac OS X; it always shows the informational text field, showing an empty string by default. On GTK+ it seems to get rid of the bold over the primary text; I'm going to assume this is intentional (it looks that way on GTK+ 2; the HIG docs have outdated screenshots...).

dialog.go

@@ -8,7 +8,8 @@ import (
 
 // MsgBox displays an informational message box to the user with just an OK button.
 // primaryText should be a short string describing the message, and will be displayed with additional emphasis on platforms that support it.
-// secondaryText can be used to provide more information.
+// Optionally, secondaryText can be used to show additional information.
+// If you pass an empty string for secondaryText, neither additional information nor space for additional information will be shown.
 // On platforms that allow for the message box window to have a title, os.Args[0] is used.
 func MsgBox(primaryText string, secondaryText string) {
 	msgBox(primaryText, secondaryText)

dialog_darwin.go

@@ -33,7 +33,9 @@ func _msgBox(primarytext string, secondarytext string, style uintptr, button0 st
 	uitask <- func() {
 		box := C.objc_msgSend_noargs(_NSAlert, _new)
 		C.objc_msgSend_id(box, _setMessageText, toNSString(primarytext))
-		C.objc_msgSend_id(box, _setInformativeText, toNSString(secondarytext))
+		if secondarytext != "" {
+			C.objc_msgSend_id(box, _setInformativeText, toNSString(secondarytext))
+		}
 		C.objc_msgSend_uint(box, _setAlertStyle, C.uintptr_t(style))
 		C.objc_msgSend_id(box, _addButtonWithTitle, toNSString(button0))
 		C.objc_msgSend_noargs(box, _runModal)

dialog_unix.go

@@ -12,7 +12,15 @@ import (
 // #include "gtk_unix.h"
 // /* because cgo seems to choke on ... */
 // /* TODO does NULL parent make the box application-global? docs are unclear */
-// GtkWidget *gtkNewMsgBox(GtkMessageType type, GtkButtonsType buttons, char *title, char *text) { GtkWidget *k = gtk_message_dialog_new(NULL, GTK_DIALOG_MODAL, type, buttons, "%s", (gchar *) title); gtk_message_dialog_format_secondary_text((GtkMessageDialog *) k, "%s", (gchar *) text); return k; }
+// GtkWidget *gtkNewMsgBox(GtkMessageType type, GtkButtonsType buttons, char *title, char *text)
+// {
+// 	GtkWidget *k;
+// 
+// 	k = gtk_message_dialog_new(NULL, GTK_DIALOG_MODAL, type, buttons, "%s", (gchar *) title);
+// 	if (text != NULL)
+// 		gtk_message_dialog_format_secondary_text((GtkMessageDialog *) k, "%s", (gchar *) text);
+// 	return k;
+// }
 import "C"
 
 func _msgBox(primarytext string, secondarytext string, msgtype C.GtkMessageType, buttons C.GtkButtonsType) (result C.gint) {
@@ -21,8 +29,11 @@ func _msgBox(primarytext string, secondarytext string, msgtype C.GtkMessageType,
 	uitask <- func() {
 		cprimarytext := C.CString(primarytext)
 		defer C.free(unsafe.Pointer(cprimarytext))
-		csecondarytext := C.CString(secondarytext)
-		defer C.free(unsafe.Pointer(csecondarytext))
+		csecondarytext := (*C.char)(nil)
+		if secondarytext != "" {
+			csecondarytext = C.CString(secondarytext)
+			defer C.free(unsafe.Pointer(csecondarytext))
+		}
 		box := C.gtkNewMsgBox(msgtype, buttons, cprimarytext, csecondarytext)
 		response := C.gtk_dialog_run((*C.GtkDialog)(unsafe.Pointer(box)))
 		C.gtk_widget_destroy(box)

dialog_windows.go

@@ -79,7 +79,10 @@ var (
 
 func _msgBox(primarytext string, secondarytext string, uType uint32) (result int) {
 	// http://msdn.microsoft.com/en-us/library/windows/desktop/aa511267.aspx says "Use task dialogs whenever appropriate to achieve a consistent look and layout. Task dialogs require Windows Vista® or later, so they aren't suitable for earlier versions of Windows. If you must use a message box, separate the main instruction from the supplemental instruction with two line breaks."
-	text := primarytext + "\n\n" + secondarytext
+	text := primarytext
+	if secondarytext != "" {
+		text += "\n\n" + secondarytext
+	}
 	ret := make(chan uiret)
 	defer close(ret)
 	uitask <- &uimsg{

futureplans.md

@@ -61,6 +61,7 @@ far off:
 	- gtk+ HIG reference: https://developer.gnome.org/hig-book/3.4/controls-lists.html.en
 	- mac HIG reference: ???
 - go over the old new thing's scrollbar series to make sure I'm doing everything right with scrollbars in Windows Areas
+- change the MsgBox() calls to encourage good alert dialog design??????? maybe? TODO
 
 big things:
 - make sure every sysData function only performs a single invocation to uitask; see http://blogs.msdn.com/b/oldnewthing/archive/2005/10/10/479124.aspx#479182

test/main.go

@@ -248,7 +248,9 @@ func myMain() {
 	w := NewWindow("Main Window", 320, 240)
 	b := NewButton("Click Me")
 	b2 := NewButton("Or Me")
-	s2 := NewHorizontalStack(b, b2)
+	bmsg := NewButton("Or Even Me!")
+	s2 := NewHorizontalStack(b, b2, bmsg)
+	s2.SetStretchy(2)
 	c := NewCheckbox("Check Me")
 	cb1 := NewEditableCombobox("You can edit me!", "Yes you can!", "Yes you will!")
 	cb2 := NewCombobox("You can't edit me!", "No you can't!", "No you won't!")
@@ -371,6 +373,9 @@ _=curtime
 			pbar.SetProgress(-1)
 		case <-invalidButton.Clicked:
 			invalidTest(cb1, lb1, nil, nil)
+		case <-bmsg.Clicked:
+			MsgBox("Title Only", "")
+			MsgBox("Title and Text", "Text and Title")
 		}
 	}
 	w.Hide()

todo.md

@@ -1,6 +1,5 @@
 so I don't forget:
 - should Labels be selectable?
-- Message boxes should not show secondary text if none is specified. [TODO figure out what I meant by this]
 - add bounds checking to Area's sizing methods
 - describe thread-safety of Area.SetSize()
 - should all instances of -1 as error returns from Windows functions be changed to ^0 or does the uintptr() conversion handle sign extension?