To support another start page than the hard coded "StartPage" you can modify the subform "FormFooter" in the appropiate calculated field to:
startPages := @DbColumn("Notes":"NoCache"; ""; "rootpages"; 3);
url1 := "/" + dbPath + "/Wiki?OpenForm&Title=StartPage";
url2 := "/" + dbPath + "/Pages/StartPage";
url3 := "/" + dbPath + "/Pages/" + @Subset(startPages;1);
test := @DbLookup("Notes" : "Cache"; ""; "Pages"; "StartPage"; 1);
@If(
!@IsError(url3) & @Length(url3) > 0; url3;<br/>
test="" | @IsError(test); url1;<br/>
url2<br/>
)