Problem with YouTube 360p quality download

I went to YouTube and clicked the green arrow button on thumbnail for quick download, then after I selected the 360p video quality---a video playback of that quality popped out instead of asking a save location that I would like to choose for download as usual... this happens on every YouTube videos... I could right-clicked on the video quality selection for "Save Link As" but that would be inconvenient, and the video would be downloaded without titles... however this problem doesn't seems to be exist for 720p quality... I have Firefox 39.0 browser with SaveForm Helper version 6.75...