Fix #168 and fix #81.

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.java

@@ -154,6 +154,14 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         }
     }
 
+    @Override
+    public void onWindowFocusChanged(boolean hasFocus) {
+        super.onWindowFocusChanged(hasFocus);
+        if (hasFocus) {
+            setSystemUiVisibility();
+        }
+    }
+
     @Override
     public boolean dispatchKeyEvent(KeyEvent event) {
         int action = event.getAction();
@@ -360,11 +368,14 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         uiFlags = 0;
         uiFlags |= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
         if (statusBarHidden) {
-            uiFlags |= View.SYSTEM_UI_FLAG_FULLSCREEN;
-            uiFlags |= View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
+            uiFlags |= View.SYSTEM_UI_FLAG_LAYOUT_STABLE
+                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
+                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+                    | View.SYSTEM_UI_FLAG_FULLSCREEN;
         }
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
             uiFlags |= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
+        }
     }
 
     public void setSystemUiVisibility() {