Ok follow my steps here-
Step-1 : Open your plugin directory and then open accordion-shortcode-and-widget plugin folder.
Step-2 : now open lib folder and then installation folder
Step-3 : In installation you will see a file installation.php open it on any editor .
Step-4 : Go to near line no. 23 and then find below code there –
add_action('media_buttons_context', 'wpsm_ac_sh_editor_popup_content_button');
add_action('admin_footer', 'wpsm_ac_sh_editor_popup_content');
Step-5: replace it with this code –
//add_action('media_buttons_context', 'wpsm_ac_sh_editor_popup_content_button');
//add_action('admin_footer', 'wpsm_ac_sh_editor_popup_content');
save you code and then check the slider plugin.