diff --git a/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentPagerExtension.kt b/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentPagerExtension.kt
index d4a8a3a..77a2bf8 100644
--- a/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentPagerExtension.kt
+++ b/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentPagerExtension.kt
@@ -12,7 +12,7 @@ abstract class FragmentPagerProxyAdapter<ARG>(fragmentManager: FragmentManager)
 
     internal var items: List<ARG> = listOf()
 
-    abstract var pageTitle: ((Int, ARG) -> String)
+    abstract var pageTitle: ((Int, ARG) -> CharSequence?)
 
     abstract var item: ((Int, ARG) -> Fragment)
 
@@ -28,11 +28,11 @@ abstract class FragmentPagerProxyAdapter<ARG>(fragmentManager: FragmentManager)
 
 fun <ARG, L : List<ARG>> ViewPager.rx_fragmentsWith(observable: Observable<L>, fragmentManager: FragmentManager,
                                                     getItem: (Int, ARG) -> Fragment,
-                                                    getPageTitle: ((Int, ARG) -> String)): Subscription {
+                                                    getPageTitle: ((Int, ARG) -> CharSequence?) = { i, a -> null }): Subscription {
     val proxyAdapter = object : FragmentPagerProxyAdapter<ARG>(fragmentManager) {
 
         override var item: (Int, ARG) -> Fragment = getItem
-        override var pageTitle: ((Int, ARG) -> String) = getPageTitle
+        override var pageTitle: ((Int, ARG) -> CharSequence?) = getPageTitle
 
     }
     return rx_fragmentsWith(observable, proxyAdapter)
diff --git a/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentStatePagerExtension.kt b/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentStatePagerExtension.kt
index c177ea8..7b98915 100644
--- a/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentStatePagerExtension.kt
+++ b/reactiveandroid-appcompat-v7/src/main/kotlin/com/github/kittinunf/reactiveandroid/support/v7/widget/FragmentStatePagerExtension.kt
@@ -11,7 +11,7 @@ abstract class FragmentStatePagerProxyAdapter<ARG>(fragmentManager: FragmentMana
 
     internal var items: List<ARG> = listOf()
 
-    abstract var pageTitle: ((Int, ARG) -> String)
+    abstract var pageTitle: ((Int, ARG) -> CharSequence?)
 
     abstract var item: ((Int, ARG) -> Fragment)
 
@@ -25,11 +25,11 @@ abstract class FragmentStatePagerProxyAdapter<ARG>(fragmentManager: FragmentMana
 
 fun <ARG, L : List<ARG>> ViewPager.rx_fragmentsStateWith(observable: Observable<L>, fragmentManager: FragmentManager,
                                                          getItem: (Int, ARG) -> Fragment,
-                                                         getPageTitle: ((Int, ARG) -> String)): Subscription {
+                                                         getPageTitle: ((Int, ARG) -> CharSequence?) = { i, a -> null }): Subscription {
     val proxyAdapter = object : FragmentStatePagerProxyAdapter<ARG>(fragmentManager) {
 
         override var item: (Int, ARG) -> Fragment = getItem
-        override var pageTitle: ((Int, ARG) -> String) = getPageTitle
+        override var pageTitle: ((Int, ARG) -> CharSequence?) = getPageTitle
 
     }
     return rx_fragmentsStateWith(observable, proxyAdapter)
@@ -39,6 +39,6 @@ fun <ARG, ADT : FragmentStatePagerProxyAdapter<ARG>, L : List<ARG>> ViewPager.rx
     adapter = fragmentPagerProxyAdapter
     return observable.subscribe {
         fragmentPagerProxyAdapter.items = it
-        post { fragmentPagerProxyAdapter.notifyDataSetChanged() }
+        fragmentPagerProxyAdapter.notifyDataSetChanged()
     }
 }
\ No newline at end of file