diff --git a/init.go b/init.go
index 1f6d542..a47266c 100644
--- a/init.go
+++ b/init.go
@@ -1,20 +1,11 @@
 // 11 february 2014
 package ui
 
-import (
-	"os"
-)
-
-func init() {
-	initDone := make(chan error)
-	go ui(initDone)
-	err := <-initDone
-	if err != nil {
-		// TODO provide copying instructions? will need to be system-specific
-		MsgBoxError("UI Library Init Failure",
-			"A failure occured during UI library initialization:\n%v\n" +
-			"Please report this to the application developer or on http://github.com/andlabs/ui.",
-			err)
-		os.Exit(1)
-	}
+// Go sets up the UI environment and runs main in a goroutine.
+// If initialization fails, Go returns an error.
+// Otherwise, Go does not return to its caller until (unless? TODO) the application loop exits, at which point it returns nil.
+//
+// This model is undesirable, but Cocoa limitations require it.
+func Go(main func()) error {
+	return ui(main)
 }
diff --git a/test.sh b/test.sh
new file mode 100755
index 0000000..7667318
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,2 @@
+cd test
+go build main.go
diff --git a/main_test.go b/test/main.go
similarity index 96%
rename from main_test.go
rename to test/main.go
index 163024e..1984e58 100644
--- a/main_test.go
+++ b/test/main.go
@@ -1,9 +1,9 @@
 // 11 february 2014
-package ui
+package main
 
 import (
 	"fmt"
-	"testing"
+	. ".."
 )
 
 func gridWindow() (*Window, error) {
@@ -25,7 +25,7 @@ func gridWindow() (*Window, error) {
 	return w, w.Open(g)
 }
 
-func TestMain(t *testing.T) {
+func myMain() {
 	w := NewWindow("Main Window", 320, 240)
 	w.Closing = Event()
 	b := NewButton("Click Me")
@@ -119,3 +119,10 @@ mainloop:
 	gw.Hide()
 	w.Hide()
 }
+
+func main() {
+	err := Go(myMain)
+	if err != nil {
+		panic(err)
+	}
+}
diff --git a/uitask_darwin.go b/uitask_darwin.go
index 3a6d633..2fb6b45 100644
--- a/uitask_darwin.go
+++ b/uitask_darwin.go
@@ -17,7 +17,6 @@ We will create an Objective-C class goAppDelegate. It contains two methods:
 
 // #cgo LDFLAGS: -lobjc -framework Foundation -framework AppKit
 // #include "objc_darwin.h"
-// extern void appDelegate_applicationDidFinishLaunching(id, SEL, id);
 // extern void appDelegate_uitask(id, SEL, id);
 import "C"
 
@@ -27,8 +26,6 @@ func msgBoxError(string, string){}
 
 var uitask chan func()
 
-var mtret chan interface{}
-
 var (
 	_NSAutoreleasePool = objc_getClass("NSAutoreleasePool")
 	_NSValue = objc_getClass("NSValue")
@@ -38,36 +35,44 @@ var (
 	_performSelectorOnMainThread =
 		sel_getUid("performSelectorOnMainThread:withObject:waitUntilDone:")
 	_pointerValue = sel_getUid("pointerValue")
+	_run = sel_getUid("run")
 )
 
-func ui(initDone chan error) {
+func ui(main func()) error {
 	runtime.LockOSThread()
 
 	uitask = make(chan func())
-	mtret = make(chan interface{})
-	go mainThread()
-	v := <-mtret
-	if err, ok := v.(error); ok {
-		initDone <- fmt.Errorf("error initializing Cocoa: %v", err)
-		return
-	}
-	appDelegate := v.(C.id)
 
-	for f := range uitask {
-		// we need to make an NSAutoreleasePool, otherwise we get leak warnings on stderr
-		pool := objc_new(_NSAutoreleasePool)
-		fp := C.objc_msgSend_ptr(_NSValue, _valueWithPointer,
-			unsafe.Pointer(&f))
-		C.objc_msgSend_sel_id_bool(
-			appDelegate,
-			_performSelectorOnMainThread,
-			_uitask,
-			fp,
-			C.BOOL(C.YES))			// wait so we can properly drain the autorelease pool; on other platforms we wind up waiting anyway (since the main thread can only handle one thing at a time) so
-		objc_release(pool)
+	NSApp, appDelegate, err := initCocoa()
+	if err != nil {
+		return err
 	}
+
+	// Cocoa must run on the first thread created by the program, so we run our dispatcher on another thread instead
+	go func() {
+		for f := range uitask {
+			// we need to make an NSAutoreleasePool, otherwise we get leak warnings on stderr
+			pool := objc_new(_NSAutoreleasePool)
+			fp := C.objc_msgSend_ptr(_NSValue, _valueWithPointer,
+				unsafe.Pointer(&f))
+			C.objc_msgSend_sel_id_bool(
+				appDelegate,
+				_performSelectorOnMainThread,
+				_uitask,
+				fp,
+				C.BOOL(C.YES))			// wait so we can properly drain the autorelease pool; on other platforms we wind up waiting anyway (since the main thread can only handle one thing at a time) so
+			objc_release(pool)
+		}
+	}()
+
+	go main()
+
+	C.objc_msgSend_noargs(NSApp, _run)
+	return nil
 }
 
+// TODO move to init_darwin.go?
+
 const (
 	_goAppDelegate = "goAppDelegate"
 )
@@ -76,41 +81,22 @@ var (
 	_NSApplication = objc_getClass("NSApplication")
 
 	_sharedApplication = sel_getUid("sharedApplication")
-	_applicationDidFinishLaunching = sel_getUid("applicationDidFinishLaunching:")
-	_run = sel_getUid("run")
 )
 
-func mainThread() {
-	runtime.LockOSThread()
+func initCocoa() (NSApp C.id, appDelegate C.id, err error) {
+	var appdelegateclass C.Class
 
-	_NSApp := C.objc_msgSend_noargs(_NSApplication, _sharedApplication)
-	appdelegateclass, err := makeDelegateClass(_goAppDelegate)
-	if err != nil {
-		mtret <- fmt.Errorf("error creating NSApplication delegate: %v", err)
-		return
-	}
-	err = addDelegateMethod(appdelegateclass, _applicationDidFinishLaunching,
-		C.appDelegate_applicationDidFinishLaunching)
-	if err != nil {
-		mtret <- fmt.Errorf("error adding NSApplication delegate applicationDidFinishLaunching: method (to start UI loop): %v", err)
-		return
-	}
+	NSApp = C.objc_msgSend_noargs(_NSApplication, _sharedApplication)
 	err = addDelegateMethod(appdelegateclass, _uitask, C.appDelegate_uitask)
 	if err != nil {
-		mtret <- fmt.Errorf("error adding NSApplication delegate uitask: method (to do UI tasks): %v", err)
+		err = fmt.Errorf("error adding NSApplication delegate uitask: method (to do UI tasks): %v", err)
 		return
 	}
 	// TODO using objc_new() causes a segfault; find out why
 	// TODO make alloc followed by init (I thought NSObject provided its own init?)
-	appDelegate := objc_alloc(objc_getClass(_goAppDelegate))
-	objc_setDelegate(_NSApp, appDelegate)
-	// and that's it, really
-	C.objc_msgSend_noargs(_NSApp, _run)
-}
+	appDelegate = objc_alloc(objc_getClass(_goAppDelegate))
 
-//export appDelegate_applicationDidFinishLaunching
-func appDelegate_applicationDidFinishLaunching(self C.id, sel C.SEL, arg C.id) {
-	mtret <- self
+	return
 }
 
 //export appDelegate_uitask
diff --git a/uitask_unix.go b/uitask_unix.go
index fad1503..759ac1d 100644
--- a/uitask_unix.go
+++ b/uitask_unix.go
@@ -10,15 +10,13 @@ import (
 
 var uitask chan func()
 
-func ui(initDone chan error) {
+func ui(main func()) error {
 	runtime.LockOSThread()
 
 	uitask = make(chan func())
 	if gtk_init() != true {
-		initDone <- fmt.Errorf("gtk_init failed (reason unknown; TODO)")
-		return
+		return fmt.Errorf("gtk_init failed (reason unknown; TODO)")
 	}
-	initDone <- nil
 
 	// thanks to tristan in irc.gimp.net/#gtk
 	gdk_threads_add_idle(func() bool {
@@ -29,5 +27,9 @@ func ui(initDone chan error) {
 		}
 		return true	// don't destroy the callback
 	})
+
+	go main()
+
 	gtk_main()
+	return nil
 }
diff --git a/uitask_windows.go b/uitask_windows.go
index c1f867c..33ab0ad 100644
--- a/uitask_windows.go
+++ b/uitask_windows.go
@@ -35,17 +35,22 @@ var (
 	_postThreadMessage = user32.NewProc("PostThreadMessageW")
 )
 
-func ui(initDone chan error) {
+func ui(main func()) error {
 	runtime.LockOSThread()
 
 	uitask = make(chan *uimsg)
-	initDone <- doWindowsInit()
+	err := doWindowsInit()
+	if err != nil {
+		return err
+	}
 
 	threadIDReq := make(chan uintptr)
 	msglooperrs := make(chan error)
 	go msgloop(threadIDReq, msglooperrs)
 	threadID := <-threadIDReq
 
+	go main()
+
 	quit := false
 	for !quit {
 		select {
@@ -66,6 +71,8 @@ func ui(initDone chan error) {
 			}
 		}
 	}
+
+	return nil
 }
 
 var (