A script add-in can close the surplus tabs after opening a new one.
function OnInit(initData) {
initData.name = 'LimitTabCount';
initData.version = '2022-07-16';
initData.url = 'https://resource.dopus.com/t/numbers-of-open-tabs/41730';
initData.desc = 'Limit number of open tabs';
initData.default_enable = true;
initData.min_version = '12.0';
}
function OnOpenTab(openTabData) {
var tab = openTabData.tab;
var tabs = tab.right ? tab.lister.tabsright : tab.lister.tabsleft;
if (tabs.count < 4) return;
var cmd = DOpus.Create().Command();
cmd.SetSourceTab(tab);
cmd.Clear();
for (var i = tabs.count; i > 3; --i) {
cmd.AddLine('Go TABCLOSE TABPOS=0');
}
cmd.Run();
}