Sometimes the progressbar is not displayed, so I decided not to hide it.

src/convertor/view.go

@@ -127,7 +127,8 @@ func (v View) getButtonFileVideoForConversion(form *widget.Form, progress *widge
 				setStringSuccessStyle(fileVideoForConversionMessage)
 
 				form.Enable()
-				progress.Hide()
+				progress.Value = 0
+				progress.Refresh()
 				conversionMessage.Text = ""
 			}, v.w)
 		fileDialog.Show()

src/handler/convertor.go

@@ -153,7 +153,6 @@ func (p progress) Run(stdOut io.ReadCloser, stdErr io.ReadCloser) error {
 
 	p.progressbar.Value = 0
 	p.progressbar.Max = p.totalDuration
-	p.progressbar.Show()
 	p.progressbar.Refresh()
 
 	progress := 0.0