How to forbidden trotoiseMerge in Vs2017 use the built-in merge tool

Question

I installed TortoiseSVN in PC and VisualSVN plug-in in Visual Studio 2017. I use SVN to manage my code.But when i merge the code, i prefer the plug-in merge tool in vs2017 like below but sometimes it automatic use the trotoiseMerge like below i want to forbidden trotoiseMerge when using vs2017 how can i do it,I appreciate every suggestion

i already choose use the built-in tools,but some file always use the TortoiseSVN, I can't tell the difference between the two