diff --git a/element.go b/element.go
index 00bc4d9..022f0b2 100644
--- a/element.go
+++ b/element.go
@@ -193,38 +193,13 @@ func (e *Element) Remove(htmlId string) {
 	e.queue(what.Remove, htmlId)
 }
 
-// ParseParams parses the parameters passed to UI() when creating a new Element,
-// setting event handlers and returning a list of HTML attributes.
-func (e *Element) ParseParams(params []any) (attrs []template.HTMLAttr) {
+// ApplyParams parses the parameters passed to UI() when creating a new Element,
+// adding UI tags, setting event handlers and returning a list of HTML attributes.
+func (e *Element) ApplyParams(params []any) []template.HTMLAttr {
+	tags, handlers, attrs := ParseParams(params)
 	if !e.deleted {
-		for i := range params {
-			switch data := params[i].(type) {
-			case template.HTMLAttr:
-				attrs = append(attrs, data)
-			case []template.HTMLAttr:
-				attrs = append(attrs, data...)
-			case string:
-				attr := template.HTMLAttr(data) // #nosec G203
-				attrs = append(attrs, attr)
-			case []string:
-				for _, s := range data {
-					attr := template.HTMLAttr(s) // #nosec G203
-					attrs = append(attrs, attr)
-				}
-			case EventFn:
-				if data != nil {
-					e.handlers = append(e.handlers, eventFnWrapper{data})
-				}
-			default:
-				if h, ok := data.(ClickHandler); ok {
-					e.handlers = append(e.handlers, clickHandlerWapper{h})
-				}
-				if h, ok := data.(EventHandler); ok {
-					e.handlers = append(e.handlers, h)
-				}
-				e.Tag(data)
-			}
-		}
+		e.handlers = append(e.handlers, handlers...)
+		e.Tag(tags...)
 	}
-	return
+	return attrs
 }
diff --git a/parseparams.go b/parseparams.go
new file mode 100644
index 0000000..6cc54a8
--- /dev/null
+++ b/parseparams.go
@@ -0,0 +1,37 @@
+package jaws
+
+import "html/template"
+
+// ParseParams parses the parameters passed to UI() when creating a new Element,
+// returning UI tags, event handlers and HTML attributes.
+func ParseParams(params []any) (tags []any, handlers []EventHandler, attrs []template.HTMLAttr) {
+	for i := range params {
+		switch data := params[i].(type) {
+		case template.HTMLAttr:
+			attrs = append(attrs, data)
+		case []template.HTMLAttr:
+			attrs = append(attrs, data...)
+		case string:
+			attr := template.HTMLAttr(data) // #nosec G203
+			attrs = append(attrs, attr)
+		case []string:
+			for _, s := range data {
+				attr := template.HTMLAttr(s) // #nosec G203
+				attrs = append(attrs, attr)
+			}
+		case EventFn:
+			if data != nil {
+				handlers = append(handlers, eventFnWrapper{data})
+			}
+		default:
+			if h, ok := data.(ClickHandler); ok {
+				handlers = append(handlers, clickHandlerWapper{h})
+			}
+			if h, ok := data.(EventHandler); ok {
+				handlers = append(handlers, h)
+			}
+			tags = append(tags, data)
+		}
+	}
+	return
+}
diff --git a/request.go b/request.go
index 4c14fcb..20123d9 100644
--- a/request.go
+++ b/request.go
@@ -289,7 +289,7 @@ func (rq *Request) Register(tagitem any, params ...any) jid.Jid {
 	case jid.Jid:
 		if elem := rq.getElementByJid(data); elem != nil {
 			if _, ok := elem.Ui().(*UiHtml); ok {
-				elem.ParseParams(params)
+				elem.ApplyParams(params)
 			}
 		}
 		return data
@@ -300,7 +300,7 @@ func (rq *Request) Register(tagitem any, params ...any) jid.Jid {
 	uib := &UiHtml{}
 	elem := rq.NewElement(uib)
 	uib.parseGetter(elem, tagitem)
-	elem.ParseParams(params)
+	elem.ApplyParams(params)
 	return elem.Jid()
 }
 
diff --git a/template.go b/template.go
index 5fcd752..1cacceb 100644
--- a/template.go
+++ b/template.go
@@ -44,7 +44,7 @@ func (t Template) JawsRender(e *Element, w io.Writer, params []any) error {
 		e.Request.tagExpanded(e, expandedtags)
 	}
 	var sb strings.Builder
-	for _, s := range e.ParseParams(params) {
+	for _, s := range e.ApplyParams(params) {
 		sb.WriteByte(' ')
 		sb.WriteString(string(s))
 	}
diff --git a/uihtmlinner.go b/uihtmlinner.go
index cc0c5d3..6014e88 100644
--- a/uihtmlinner.go
+++ b/uihtmlinner.go
@@ -11,7 +11,7 @@ type UiHtmlInner struct {
 
 func (ui *UiHtmlInner) renderInner(e *Element, w io.Writer, htmltag, htmltype string, params []any) error {
 	ui.parseGetter(e, ui.HtmlGetter)
-	return WriteHtmlInner(w, e.Jid(), htmltag, htmltype, ui.JawsGetHtml(e), e.ParseParams(params)...)
+	return WriteHtmlInner(w, e.Jid(), htmltag, htmltype, ui.JawsGetHtml(e), e.ApplyParams(params)...)
 }
 
 func (ui *UiHtmlInner) JawsUpdate(e *Element) {
diff --git a/uiimg.go b/uiimg.go
index 8ae410f..6974a4e 100644
--- a/uiimg.go
+++ b/uiimg.go
@@ -14,7 +14,7 @@ type UiImg struct {
 func (ui *UiImg) JawsRender(e *Element, w io.Writer, params []any) error {
 	ui.parseGetter(e, ui.StringGetter)
 	srcattr := template.HTMLAttr("src=" + strconv.Quote(ui.JawsGetString(e))) // #nosec G203
-	attrs := append(e.ParseParams(params), srcattr)
+	attrs := append(e.ApplyParams(params), srcattr)
 	return WriteHtmlInner(w, e.Jid(), "img", "", "", attrs...)
 }
 
diff --git a/uiinputbool.go b/uiinputbool.go
index 10dcb0b..62d758f 100644
--- a/uiinputbool.go
+++ b/uiinputbool.go
@@ -14,7 +14,7 @@ type UiInputBool struct {
 
 func (ui *UiInputBool) renderBoolInput(e *Element, w io.Writer, htmltype string, params ...any) error {
 	ui.parseGetter(e, ui.BoolSetter)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	v := ui.JawsGetBool(e)
 	ui.Last.Store(v)
 	if v {
diff --git a/uiinputdate.go b/uiinputdate.go
index 574150a..b542e6c 100644
--- a/uiinputdate.go
+++ b/uiinputdate.go
@@ -18,7 +18,7 @@ func (ui *UiInputDate) str() string {
 
 func (ui *UiInputDate) renderDateInput(e *Element, w io.Writer, htmltype string, params ...any) error {
 	ui.parseGetter(e, ui.TimeSetter)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	ui.Last.Store(ui.JawsGetTime(e))
 	return WriteHtmlInput(w, e.Jid(), htmltype, ui.str(), attrs)
 }
diff --git a/uiinputfloat.go b/uiinputfloat.go
index c267df9..df7c6e9 100644
--- a/uiinputfloat.go
+++ b/uiinputfloat.go
@@ -18,7 +18,7 @@ func (ui *UiInputFloat) str() string {
 
 func (ui *UiInputFloat) renderFloatInput(e *Element, w io.Writer, htmltype string, params ...any) error {
 	ui.parseGetter(e, ui.FloatSetter)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	ui.Last.Store(ui.JawsGetFloat(e))
 	return WriteHtmlInput(w, e.Jid(), htmltype, ui.str(), attrs)
 }
diff --git a/uiinputtext.go b/uiinputtext.go
index 954c5bb..a98016a 100644
--- a/uiinputtext.go
+++ b/uiinputtext.go
@@ -13,7 +13,7 @@ type UiInputText struct {
 
 func (ui *UiInputText) renderStringInput(e *Element, w io.Writer, htmltype string, params ...any) error {
 	ui.parseGetter(e, ui.StringSetter)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	v := ui.JawsGetString(e)
 	ui.Last.Store(v)
 	return WriteHtmlInput(w, e.Jid(), htmltype, v, attrs)
diff --git a/uioption.go b/uioption.go
index d9af520..2eaacdb 100644
--- a/uioption.go
+++ b/uioption.go
@@ -10,7 +10,7 @@ type UiOption struct{ *NamedBool }
 
 func (ui UiOption) JawsRender(e *Element, w io.Writer, params []any) error {
 	e.Tag(ui.NamedBool)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	valattr := template.HTMLAttr(`value="` + html.EscapeString(ui.JawsGetString(e)) + `"`) // #nosec G203
 	attrs = append(attrs, valattr)
 	if ui.Checked() {
diff --git a/uitemplate.go b/uitemplate.go
index 79dd8ea..4d9eae7 100644
--- a/uitemplate.go
+++ b/uitemplate.go
@@ -13,6 +13,9 @@ func NewUiTemplate(t Template) UiTemplate {
 //
 // The templ argument can either be a string, in which case Jaws.Template.Lookup() will
 // be used to resolve it. Or it can be a *template.Template directly.
+//
+// Note that templates are only rendered once; adding UI tags to a template
+// have no effect, since JawsUpdate is a no-op for them.
 func (rq RequestWriter) Template(templ, dot any, params ...any) error {
 	return rq.UI(NewUiTemplate(rq.rq.MakeTemplate(templ, dot)), params...)
 }
diff --git a/uitextarea.go b/uitextarea.go
index acd67f3..d7cda82 100644
--- a/uitextarea.go
+++ b/uitextarea.go
@@ -11,7 +11,7 @@ type UiTextarea struct {
 
 func (ui *UiTextarea) JawsRender(e *Element, w io.Writer, params []any) error {
 	ui.parseGetter(e, ui.StringSetter)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	return WriteHtmlInner(w, e.Jid(), "textarea", "", template.HTML(ui.JawsGetString(e)), attrs...) // #nosec G203
 }
 
diff --git a/uiwrapcontainer.go b/uiwrapcontainer.go
index b7cde2c..a5f2d44 100644
--- a/uiwrapcontainer.go
+++ b/uiwrapcontainer.go
@@ -18,7 +18,7 @@ type uiWrapContainer struct {
 
 func (ui *uiWrapContainer) renderContainer(e *Element, w io.Writer, outerhtmltag string, params []any) (err error) {
 	ui.parseGetter(e, ui.Container)
-	attrs := e.ParseParams(params)
+	attrs := e.ApplyParams(params)
 	b := e.Jid().AppendStartTagAttr(nil, outerhtmltag)
 	for _, attr := range attrs {
 		b = append(b, ' ')