core/rootview: fix dnd multiple folders into dock

data/core/rootview.lua

@@ -24,7 +24,7 @@ function RootView:new()
                             base_color = style.drag_overlay_tab,
                             color = { table.unpack(style.drag_overlay_tab) } }
   self.drag_overlay_tab.to = { x = 0, y = 0, w = 0, h = 0 }
-  self.first_update_done = false
+  self.first_dnd_processed = false
 end
 
 
@@ -324,7 +324,7 @@ function RootView:on_file_dropped(filename, x, y)
   if result then return result end
   local info = system.get_file_info(filename)
   if info and info.type == "dir" then
-    if self.first_update_done then
+    if self.first_dnd_processed then
       -- first update done, open in new window
       system.exec(string.format("%q %q", EXEFILE, filename))
     else
@@ -332,6 +332,7 @@ function RootView:on_file_dropped(filename, x, y)
       core.confirm_close_docs(core.docs, function(dirpath)
         core.open_folder_project(dirpath)
       end, system.absolute_path(filename))
+      self.first_dnd_processed = true
     end
   else
     local ok, doc = core.try(core.open_doc, filename)
@@ -385,7 +386,9 @@ function RootView:update()
   self:update_drag_overlay()
   self:interpolate_drag_overlay(self.drag_overlay)
   self:interpolate_drag_overlay(self.drag_overlay_tab)
-  self.first_update_done = true
+  -- set this to true because at this point there are no dnd requests
+  -- that are caused by the initial dnd into dock user action
+  self.first_dnd_processed = true
 end