diff -up system-config-kdump-2.0.13/src/system-config-kdump.py.support_crashkernel_extended_options system-config-kdump-2.0.13/src/system-config-kdump.py
--- system-config-kdump-2.0.13/src/system-config-kdump.py.support_crashkernel_extended_options	2017-09-25 16:46:24.653213434 +0200
+++ system-config-kdump-2.0.13/src/system-config-kdump.py	2017-09-25 16:54:46.416394396 +0200
@@ -100,6 +100,7 @@ AUTHORS = [
     "Dave Lehman <dlehman@redhat.com>",
     "Jarod Wilson <jwilson@redhat.com>",
     "Roman Rakus <rrakus@redhat.com>",
+    "Than Ngo <than@redhat.com>",
     ]
 
 LICENSE = _(
@@ -1292,6 +1293,30 @@ class MainWindow:
             self.menu_disable.set_sensitive(False)
         self.check_settings()
 
+    def crashkernel_use_offset(self, state):
+        """
+        It's called whenever the crashkernel option has offset like 128@16M or 512M-2G:64M,2G-:128@16M
+        Set up sensitive of widgets. If offset is used the Manual radion button will be disable and 
+        only expert settings allows the user to enter the extended options.
+        """
+        self.manualdump_radiobutton.set_sensitive(state)
+        self.manualdump_radiobutton.set_active(not state)
+        self.total_mem_label.set_sensitive(state)
+        self.kdump_mem_current_label.set_sensitive(state)
+        self.kdump_mem_spin_button.set_sensitive(state)
+        self.usable_mem_label.set_sensitive(state)
+        self.memory_table.set_sensitive(state)
+
+    def check_crashkernel_use_offset(self):
+        """"
+        It's called when you want to check whether crashkernel uses offset like
+        128@16M or 512M-2G:64M,2G-:128@16M
+        """
+        if self.get_crashkernel(self.my_settings.commandline).find("@") != -1:
+           return True
+        else:
+           return False
+
     def target_type_changed(self, button):
         """
         It's callled whenever you choose one of target type.
@@ -1548,12 +1573,13 @@ class MainWindow:
             if use_auto:
                 gtk_entry.set_text(old_text.replace(old_value,"auto"))
             else:
-                if size != 0:
-                    gtk_entry.set_text(old_text.replace(old_value,
-                        "%dM" % size))
-                else:
-                    gtk_entry.set_text(old_text.replace(" crashkernel=%s" \
-                        %old_value, ""))
+                if not self.check_crashkernel_use_offset():
+                    if size != 0:
+                        gtk_entry.set_text(old_text.replace(old_value,
+                            "%dM" % size))
+                    else:
+                        gtk_entry.set_text(old_text.replace(" crashkernel=%s" \
+                            %old_value, ""))
         self.my_settings.commandline = gtk_entry.get_text()
         self.my_settings.kdump_mem = size
 
@@ -1597,6 +1623,8 @@ class MainWindow:
             if value == "auto":
                 self.auto_radiobutton.set_active(True)
                 self.kdump_auto_toggled(self.auto_radiobutton)
+            elif value.find("@") != -1:
+                self.crashkernel_use_offset(False)
             else:
                 size = None
                 offset = None
@@ -2056,6 +2084,9 @@ class MainWindow:
         if DEBUG:
             print "kdump auto toggled; using auto? %s, using fadump? %s" \
                 % (is_auto, is_fadump)
+
+        self.crashkernel_use_offset(not self.check_crashkernel_use_offset()) 
+
         self.check_settings()
 
 if __name__ == "__main__":