AutoHotkey: GUI for retention/removal operation applied on clipboard

Hello experts,

I set up the following AutoHotkey script in order to retain or remove lines from a clipboard based on string reported in the GUI.

+^r::
AddTextEditWidth:=400
Gui,Add,Text
Gui,Add,Text,xm,Which operation to you want to performed?
Gui,Add,Radio,Checked vWhichOp xm,Retain
Gui,Add,Radio,x+20,Remove
Gui,Add,Text
Gui,Add,Text,xm,Enter the string related to retain or remove operation (or click Cancel not to add text):
Gui,Add,Edit,vAddTextRetainRemove xm w%AddTextEditWidth%
Gui,Add,Text
Gui,Add,Button,xm gButtonAddTextRetainRemoveOK Default,&OK
Gui,Add,Button,x+10 gButtonAddTextRetainRemoveCancel,&Cancel
Gui,Show,,Add text
Return

ButtonAddTextRetainRemoveOK:
Gui,Submit
Gui,Destroy
Send, ^c
ClipWait,1
If (ErrorLevel=1)
{
  MsgBox,4144,Error,No text appeared on clipboard after initial Ctrl+c and waiting for one second
  Return
}
Else
ReferenceString:=AddTextRetainRemove
NewClipboardVar:=""
Loop,Parse,Clipboard,`n,`r
If (WhichOp=1) 
{
  If InStr(A_LoopField, ReferenceString)
    NewClipboardVar:=NewClipboardVar . A_LoopField . "`n"
}
Else
{
  If InStr(A_LoopField, ReferenceString)
    Continue
    NewClipboardVar:=NewClipboardVar . A_LoopField . "`n"
}
LastChar:=SubStr(NewClipboard,0,1) ; see if last char is CR or LF
If ((LastChar="`r") or (LastChar="`n"))
{
  StringTrimRight,NewClipboard,NewClipboard,1 ; last char is CR or LF - remove it
  LastChar:=SubStr(NewClipboard,0,1) ;  see if new last char is CR or LF
  If ((LastChar="`r") or (LastChar="`n")) ;
    StringTrimRight,NewClipboard,NewClipboard,1 ; new last char is CR or LF - remove it
}
Clipboard:=NewClipboardVar
ClipWait,2
If (ErrorLevel=1)
  MsgBox,4144,Error,No text appeared on clipboard with blank lines removed after waiting for two seconds`nThis should never happen
Else
  Send ^v
ButtonAddTextRetainRemoveCancel:
Gui,Destroy
Return

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I tested on Notepad++/Windows 10 home and it works.
Certainly some aspects should be reviewed, if so please let me know.

I would also take the opportunity to ask for some help in order to add an additional GUI radio with 3 options:
-Anyway option (checked) option: retention or removal will be performed as is, if one of the lines contains anyway the string reported
-Beginning second option: retention or removal will be performed if one of the line begins with string reported
-End third option: retention or removal will be performed if one of the line ends with string reported

Thank you in advance for your help.