fix flicker issue in main view

pkg/gui/tasks_adapter.go

@@ -83,13 +83,23 @@ func (gui *Gui) getManager(view *gocui.View) *tasks.ViewBufferManager {
 			gui.Log,
 			view,
 			func() {
-				view.Clear()
+				// we could clear here, but that actually has the effect of causing a flicker
+				// where the view may contain no content momentarily as the gui refreshes.
+				// Instead, we're rewinding the write pointer so that we will just start
+				// overwriting the existing content from the top down. Once we've reached
+				// the end of the content do display, we call view.FlushStaleCells() to
+				// clear out the remaining content from the previous render.
+				view.Rewind()
 			},
 			func() {
 				gui.g.Update(func(*gocui.Gui) error {
 					return nil
 				})
-			})
+			},
+			func() {
+				view.FlushStaleCells()
+			},
+		)
 		gui.viewBufferManagerMap[view.Name()] = manager
 	}