Expand the Folder Tree when Clicked or Hovered, then revert when not

Help & Support
2

I happen to have seen this:
Autohide folder tree by mouse - Tools - Directory Opus Resource Centre (dopus.com)
I'm not familiar with AHK, removed some code.

#SingleInstance, Force
#Persistent
DetectHiddenWindows, On
#NoTrayIcon

;DOpusrt path
        If (!DOpusrt)
		{
          IfExist, C:\Program Files\GPSoftware\Directory Opus\dopusrt.exe
          {
            DOpusrt := "C:\Program Files\GPSoftware\Directory Opus\dopusrt.exe"
          }
          else IfExist, C:\Program Files\Directory Opus\dopusrt.exe
          {
            DOpusrt := "C:\Program Files\Directory Opus\dopusrt.exe"
          }
		  else IfExist, D:\Program Files\GPSoftware\Directory Opus\dopusrt.exe
          {
            DOpusrt := "D:\Program Files\GPSoftware\Directory Opus\dopusrt.exe"
          }
		  else IfExist, D:\Program Files\Directory Opus\dopusrt.exe
          {
            DOpusrt := "D:\Program Files\Directory Opus\dopusrt.exe"
          }
		  else IfExist, D:\Tools\GPSoftware\Directory Opus\dopusrt.exe
          {
            DOpusrt := "D:\Tools\GPSoftware\Directory Opus\dopusrt.exe"
          }
		  else IfExist, D:\Tools\Directory Opus\dopusrt.exe
          {
            DOpusrt := "D:\Tools\Directory Opus\dopusrt.exe"
          }
		  else IfExist, E:\Program Files\GPSoftware\Directory Opus\dopusrt.exe
          {
            DOpusrt := "E:\Program Files\GPSoftware\Directory Opus\dopusrt.exe"
          }
		  else IfExist, F:\Program Files\GPSoftware\Directory Opus\dopusrt.exe
          {
            DOpusrt := "F:\Program Files\GPSoftware\Directory Opus\dopusrt.exe"
          }
		  else
		  {
		  MsgBox, dopusrt.exe is not found!`n`nPlease modify the path of dopusrt.exe in the ahk code
		  return
		  }
		}

SetTimer, MGP, 50
Return
switch := ""
MGP:
DPL = dopus.lister
IfWinActive, ahk_class dopus.lister 
{
        WinGetClass, mC, ahk_id %fID%
        MouseGetPos, fX, fY, fID, fWin
        If(mC < > DPL) {
        Return
    }
    WinGetPos, dX, dY, dW, dH, ahk_classdopus.lister
    ControlGet, CG, Enabled, , SysTreeView321, ahk_classdopus.lister
        SetTimer, MGP, Off
        Sleep, 125
		If(fX > 300 && fX < dW - 40 && fY > 90 && fY < dH - 40 && switch == 2) {              ;Mouse hover area, fX > 300 && fX < dW - 40 refers to the X coordinate area from the left side of the window 300px to the right
		run, %DOpusrt% /cmd Set FOLDERTREESIZE 300,300                                        ;Pass command to DOpus to resize tree to 300,300
		switch := ""
		}
		If(fX < 300 && fX > 0 && fY > 90 && fY < dH - 40 && switch == "") {                   ;Mouse hover area, fX < 300 && fX > 0 refers to the X coordinate area 300px from the left side of the window to the right
		run, %DOpusrt% /cmd Set FOLDERTREESIZE 800,300                                        ;Pass command to DOpus to resize tree to 800,300
		switch := 2
		}
        Sleep, 125
        SetTimer, MGP, On
        Return
}