diff --git a/lightweight_charts/abstract.py b/lightweight_charts/abstract.py
index 30c8b55..7e2a725 100644
--- a/lightweight_charts/abstract.py
+++ b/lightweight_charts/abstract.py
@@ -141,6 +141,7 @@ def __init__(self, chart: 'AbstractChart', name: str = None):
         self.name = name
         self.num_decimals = 2
         self.offset = 0
+        self.data = pd.DataFrame()
 
     def _set_interval(self, df: pd.DataFrame):
         if not pd.api.types.is_datetime64_any_dtype(df['time']):
@@ -216,6 +217,7 @@ def _single_datetime_format(self, arg):
     def set(self, df: pd.DataFrame = None, format_cols: bool = True):
         if df is None or df.empty:
             self.run_script(f'{self.id}.series.setData([])')
+            self.data = pd.DataFrame()
             return
         if format_cols:
             df = self._df_datetime_format(df, exclude_lowercase=self.name)
@@ -223,6 +225,7 @@ def set(self, df: pd.DataFrame = None, format_cols: bool = True):
             if self.name not in df:
                 raise NameError(f'No column named "{self.name}".')
             df = df.rename(columns={self.name: 'value'})
+        self.data = df.copy()
         self._last_bar = df.iloc[-1]
         self.run_script(f'{self.id}.series.setData({js_data(df)})')
 
@@ -230,6 +233,9 @@ def update(self, series: pd.Series):
         series = self._series_datetime_format(series, exclude_lowercase=self.name)
         if self.name in series.index:
             series.rename({self.name: 'value'}, inplace=True)
+        if series['time'] != self._last_bar['time']:
+            self.data.loc[self.data.index[-1]] = self._last_bar
+            self.data = pd.concat([self.data, series.to_frame().T], ignore_index=True)
         self._last_bar = series
         self.run_script(f'{self.id}.series.update({js_data(series)})')
 
diff --git a/lightweight_charts/chart.py b/lightweight_charts/chart.py
index 2f70c25..4ac21e0 100644
--- a/lightweight_charts/chart.py
+++ b/lightweight_charts/chart.py
@@ -34,7 +34,11 @@ def __init__(self, q, start_ev, exit_ev, loaded, emit_queue, return_queue, html,
     def create_window(self, width, height, x, y, screen=None, on_top=False, maximize=False):
         screen = webview.screens[screen] if screen is not None else None
         if maximize:
-            width, height = screen.width, screen.height
+            if screen is None:
+                active_screen = webview.screens[0]
+                width, height = active_screen.width, active_screen.height
+            else:
+                width, height = screen.width, screen.height
         self.windows.append(webview.create_window(
             '', html=self.html, js_api=self.callback_api,
             width=width, height=height, x=x, y=y, screen=screen,
diff --git a/lightweight_charts/util.py b/lightweight_charts/util.py
index 1d38f97..ef3583c 100644
--- a/lightweight_charts/util.py
+++ b/lightweight_charts/util.py
@@ -99,7 +99,11 @@ def __iadd__(self, other):
         return self
 
     def _emit(self, *args):
-        self._callable(*args) if self._callable else None
+        if self._callable:
+            if asyncio.iscoroutinefunction(self._callable):
+                asyncio.create_task(self._callable(*args))
+            else:
+                self._callable(*args)
 
 
 class JSEmitter:
diff --git a/setup.py b/setup.py
index 0dae59b..262c15f 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
 setup(
     name='lightweight_charts',
-    version='1.0.18',
+    version='1.0.18.2',
     packages=find_packages(),
     python_requires='>=3.8',
     install_requires=[