Fix switching double-page mode

app/src/main/kotlin/org/koitharu/kotatsu/core/ui/list/lifecycle/PagerLifecycleDispatcher.kt

@@ -19,6 +19,10 @@ class PagerLifecycleDispatcher(
 		setResumedPage(pager.currentItem)
 	}
 
+	fun postInvalidate() = pager.post {
+		invalidate()
+	}
+
 	private fun setResumedPage(position: Int) {
 		pendingUpdate?.cancel()
 		pendingUpdate = null

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/ReaderManager.kt

@@ -47,11 +47,12 @@ class ReaderManager(
 	}
 
 	fun setDoubleReaderMode(isEnabled: Boolean) {
-		val prevMode = currentMode
+		val mode = currentMode
+		val prevReader = currentReader?.javaClass
 		invalidateTypesMap(isEnabled && isLandscape())
-		val newMode = currentMode ?: return
-		if (newMode != prevMode) {
-			replace(newMode)
+		val newReader = modeMap[mode]
+		if (mode != null && newReader != prevReader) {
+			replace(mode)
 		}
 	}
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/BasePagerReaderFragment.kt

@@ -120,7 +120,7 @@ abstract class BasePagerReaderFragment : BaseReaderFragment<FragmentReaderPagerB
 		val items = launch {
 			requireAdapter().setItems(pages)
 			yield()
-			pagerLifecycleDispatcher?.invalidate()
+			pagerLifecycleDispatcher?.postInvalidate()
 		}
 		if (pendingState != null) {
 			val position = pages.indexOfFirst {