Sidebars do not suspend the server-side script while the dialog is open.
Google slides guides. Scripts can extend certain Google products by adding user-interface elements that when clicked execute an Apps Script function. The most common example is running a script from a custom menu item in Google Docs Sheets Slides or Forms but script functions can also be triggered by clicking on images and drawings in Google Sheets. Use keyboard shortcuts in Google Slides to navigate format and edit. Some shortcuts might not work for all languages or keyboards. To open a list of keyboard shortcuts in Google Slides press Ctrl Windows Chrome OS or Mac. To search the menus press Alt Windows Chrome OS or Option Mac.
You can also use menu access keys. A sidebar can display an HTML service user interface inside a Google Docs Forms Slides or Sheets editor.