diff --git a/beast-fx/src/main/java/beastfx/app/inputeditor/IIDInputEditor.java b/beast-fx/src/main/java/beastfx/app/inputeditor/IIDInputEditor.java
index c527f765..3412eb02 100644
--- a/beast-fx/src/main/java/beastfx/app/inputeditor/IIDInputEditor.java
+++ b/beast-fx/src/main/java/beastfx/app/inputeditor/IIDInputEditor.java
@@ -1,38 +1,19 @@
 package beastfx.app.inputeditor;
 
 
-
-
-
-
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
 import beast.base.core.BEASTInterface;
 import beast.base.core.Input;
 import beast.base.inference.Distribution;
 import beast.base.parser.PartitionContext;
-import beast.base.spec.domain.Int;
-import beast.base.spec.domain.NonNegativeInt;
-import beast.base.spec.domain.NonNegativeReal;
-import beast.base.spec.domain.PositiveInt;
-import beast.base.spec.domain.PositiveReal;
-import beast.base.spec.domain.Real;
+import beast.base.spec.domain.*;
 import beast.base.spec.inference.distribution.IID;
 import beast.base.spec.inference.distribution.ScalarDistribution;
 import beast.base.spec.inference.distribution.TensorDistribution;
-import beast.base.spec.inference.parameter.BoolScalarParam;
-import beast.base.spec.inference.parameter.IntScalarParam;
-import beast.base.spec.inference.parameter.IntVectorParam;
-import beast.base.spec.inference.parameter.RealScalarParam;
-import beast.base.spec.inference.parameter.RealVectorParam;
-import beast.base.spec.type.IntScalar;
+import beast.base.spec.inference.parameter.*;
 import beast.base.spec.type.IntVector;
-import beast.base.spec.type.RealScalar;
 import beast.base.spec.type.RealVector;
 import beast.base.spec.type.Scalar;
+import beast.base.spec.type.Simplex;
 import beastfx.app.util.FXUtils;
 import javafx.geometry.Insets;
 import javafx.scene.Node;
@@ -43,6 +24,10 @@
 import javafx.scene.layout.HBox;
 import javafx.scene.layout.Pane;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 public class IIDInputEditor extends ScalarDistributionInputEditor {
 
 	public IIDInputEditor() {
@@ -118,7 +103,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
                 List<?> list = (List<?>) m_input.get();
                 TensorDistribution<?,?> prior1 = (TensorDistribution<?,?>) list.get(itemNr);
                 BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, RealScalar.class, doc);
+                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
                 if (dlg.showDialog()) {
                     dlg.accept(p1, doc);
                     ((BEASTInterface)p1).initAndValidate();
@@ -139,7 +124,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
                 List<?> list = (List<?>) m_input.get();
                 TensorDistribution<?,?> prior1 = (TensorDistribution<?,?>) list.get(itemNr);
                 BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, IntScalar.class, doc);
+                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
                 if (dlg.showDialog()) {
                     dlg.accept(p1, doc);
                     p1.initAndValidate();
@@ -273,9 +258,10 @@ protected ComboBox<BeautiSubTemplate> createComboBox() {
         Object param = distr.paramInput.get();
         Class<?> domain = getParameterDomain(param);
         for (BeautiSubTemplate template : tensorTemplates) {
-        	if (isCompatible(domain, templateDomains.get(k++))) {
+        	if (isCompatible(domain, templateDomains.get(k), hasSimplexParam(param, templateInstances.get(k)))) {
         		comboBox.getItems().add(template);
         	}
+        	k++;
         }
         
         if (comboBox.getItems().size() == 0) {
@@ -353,12 +339,27 @@ protected void updateItem(BeautiSubTemplate item, boolean empty) {
 	}
 	
     
-	private boolean isCompatible(Class<?> paramDomain, Class<?> templateDomain) {
+	/**
+	 * Domain range checks in isCompatible() can't see the "elements sum to 1" structural
+	 * constraint of a Simplex, so a Simplex-only template must line up with a
+	 * Simplex-valued param, and a non-Simplex template must not be offered for one.
+	 */
+	private boolean hasSimplexParam(Object param, TensorDistribution<?,?> templateInstance) {
+		Object templateParam = templateInstance == null ? null : templateInstance.getInput("param").get();
+		boolean paramIsSimplex = param instanceof Simplex;
+		boolean templateIsSimplex = templateParam instanceof Simplex;
+		return paramIsSimplex == templateIsSimplex;
+	}
+
+	private boolean isCompatible(Class<?> paramDomain, Class<?> templateDomain, boolean hasSimplexParam) {
     	if (templateDomain == null) {
     		// the "no prior" and ScalarDistribution templates should be rejected
     		return false;
     	}
-    	
+    	if (!hasSimplexParam) {
+    		return false;
+    	}
+
 		if (Real.class.isAssignableFrom(paramDomain)) {
     		// check type first
     		if (!(Real.class.isAssignableFrom(templateDomain))) {
diff --git a/beast-fx/src/main/java/beastfx/app/inputeditor/ScalarDistributionInputEditor.java b/beast-fx/src/main/java/beastfx/app/inputeditor/ScalarDistributionInputEditor.java
index 1046ab70..7f257144 100644
--- a/beast-fx/src/main/java/beastfx/app/inputeditor/ScalarDistributionInputEditor.java
+++ b/beast-fx/src/main/java/beastfx/app/inputeditor/ScalarDistributionInputEditor.java
@@ -165,7 +165,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
 	                	return;
 	                }
 	                BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-	                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, RealScalar.class, doc);
+	                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
 	                if (dlg.showDialog()) {
 	                    dlg.accept(p1, doc);
 	                    ((BEASTInterface)p1).initAndValidate();
@@ -188,7 +188,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
 	                	return;
 	                }
 	                BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-	                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, IntScalar.class, doc);
+	                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
 	                if (dlg.showDialog()) {
 	                    dlg.accept(p1, doc);
 	                    p1.initAndValidate();
diff --git a/beast-fx/src/main/java/beastfx/app/inputeditor/TensorDistributionInputEditor.java b/beast-fx/src/main/java/beastfx/app/inputeditor/TensorDistributionInputEditor.java
index e48fcd12..22178875 100644
--- a/beast-fx/src/main/java/beastfx/app/inputeditor/TensorDistributionInputEditor.java
+++ b/beast-fx/src/main/java/beastfx/app/inputeditor/TensorDistributionInputEditor.java
@@ -9,7 +9,10 @@
 import beast.base.spec.inference.distribution.ScalarDistribution;
 import beast.base.spec.inference.distribution.TensorDistribution;
 import beast.base.spec.inference.parameter.*;
-import beast.base.spec.type.*;
+import beast.base.spec.type.IntVector;
+import beast.base.spec.type.RealVector;
+import beast.base.spec.type.Scalar;
+import beast.base.spec.type.Simplex;
 import beastfx.app.util.FXUtils;
 import javafx.scene.Node;
 import javafx.scene.control.Button;
@@ -98,7 +101,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
                 List<?> list = (List<?>) m_input.get();
                 TensorDistribution<?,?> prior1 = (TensorDistribution<?,?>) list.get(itemNr);
                 BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, RealScalar.class, doc);
+                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
                 if (dlg.showDialog()) {
                     dlg.accept(p1, doc);
                     ((BEASTInterface)p1).initAndValidate();
@@ -119,7 +122,7 @@ public void init(Input<?> input, BEASTInterface beastObject, int itemNr, ExpandO
                 List<?> list = (List<?>) m_input.get();
                 TensorDistribution<?,?> prior1 = (TensorDistribution<?,?>) list.get(itemNr);
                 BEASTInterface p1 = (BEASTInterface) prior1.paramInput.get();
-                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, IntScalar.class, doc);
+                BEASTObjectDialog dlg = new BEASTObjectDialog(p1, p1.getClass(), doc);
                 if (dlg.showDialog()) {
                     dlg.accept(p1, doc);
                     p1.initAndValidate();
@@ -253,9 +256,10 @@ private ComboBox<BeautiSubTemplate> createComboBox() {
         Object param = distr.paramInput.get();
         Class<?> domain = getParameterDomain(param);
         for (BeautiSubTemplate template : tensorTemplates) {
-        	if (isCompatible(domain, templateDomains.get(k++))) {
+        	if (isCompatible(domain, templateDomains.get(k), hasSimplexParam(param, templateInstances.get(k)))) {
         		comboBox.getItems().add(template);
         	}
+        	k++;
         }
         
         if (comboBox.getItems().size() == 0) {
@@ -334,12 +338,27 @@ protected void updateItem(BeautiSubTemplate item, boolean empty) {
 	}
 	
     
-	private boolean isCompatible(Class<?> paramDomain, Class<?> templateDomain) {
+	/**
+	 * Domain range checks in isCompatible() can't see the "elements sum to 1" structural
+	 * constraint of a Simplex, so a Simplex-only template must line up with a
+	 * Simplex-valued param, and a non-Simplex template must not be offered for one.
+	 */
+	private boolean hasSimplexParam(Object param, TensorDistribution<?,?> templateInstance) {
+		Object templateParam = templateInstance == null ? null : templateInstance.getInput("param").get();
+		boolean paramIsSimplex = param instanceof Simplex;
+		boolean templateIsSimplex = templateParam instanceof Simplex;
+		return paramIsSimplex == templateIsSimplex;
+	}
+
+	private boolean isCompatible(Class<?> paramDomain, Class<?> templateDomain, boolean hasSimplexParam) {
     	if (templateDomain == null) {
     		// the "no prior" and ScalarDistribution templates should be rejected
     		return false;
     	}
-    	
+    	if (!hasSimplexParam) {
+    		return false;
+    	}
+
 		if (Real.class.isAssignableFrom(paramDomain)) {
     		// check type first
     		if (!(Real.class.isAssignableFrom(templateDomain))) {
diff --git a/beast-fx/src/main/resources/beast.fx/fxtemplates/ParametricDistributions.xml b/beast-fx/src/main/resources/beast.fx/fxtemplates/ParametricDistributions.xml
index 139c5e42..bebbdaba 100644
--- a/beast-fx/src/main/resources/beast.fx/fxtemplates/ParametricDistributions.xml
+++ b/beast-fx/src/main/resources/beast.fx/fxtemplates/ParametricDistributions.xml
@@ -33,13 +33,6 @@
 ]]>
         </subtemplate>
 
-        <!-- OneOnX -->
-        <subtemplate id='1/X' class='beast.base.inference.distribution.OneOnX' mainid='[top]'>
-            <![CDATA[        
-            <distr spec="beast.base.inference.distribution.OneOnX"/>
-]]>
-        </subtemplate>
-
         <!-- lognormal -->
         <subtemplate id='LogNormal' class='beast.base.spec.inference.distribution.LogNormal' mainid='[top]'
         	suppressInputs='beast.base.spec.inference.distribution.LogNormal.param'
@@ -188,6 +181,21 @@
 ]]>
         </subtemplate>
 
+        <!-- OneOnX (improper 1/x prior) is removed from the BEAUti distribution list; -->
+        <!-- use LogUniform as a replacement to a PositiveReal-domain param bounded on [lower, upper]. -->
+        <subtemplate id='LogUniform' class='beast.base.spec.inference.distribution.LogUniform' mainid='[top]'
+                     suppressInputs='beast.base.spec.inference.distribution.LogUniform.param'
+                     hmc='
+			LogUniform/lower/=ParametricDistributions/LogUniform/lower/,
+			LogUniform/upper/=ParametricDistributions/LogUniform/upper/'>
+            <![CDATA[
+        <distr spec="beast.base.spec.inference.distribution.LogUniform">
+                <lower spec="beast.base.spec.inference.parameter.RealScalarParam" domain="PositiveReal" value="1.0E-8" estimate="false"/>
+                <upper spec="beast.base.spec.inference.parameter.RealScalarParam" domain="PositiveReal" value="1.0E8" estimate="false"/>
+        </distr>
+]]>
+        </subtemplate>
+
         <!-- Poisson -->
         <subtemplate id='Poisson' class='beast.base.spec.inference.distribution.Poisson' mainid='[top]'
         	suppressInputs='beast.base.spec.inference.distribution.Poisson.param'
@@ -201,12 +209,17 @@
         </subtemplate>
 
         <!-- Dirichlet -->
+        <!-- The "param" below is hidden from the user (see suppressInputs) and its value is never used. -->
+        <!-- BEAUti still needs it to recognize Dirichlet as a valid prior for simplex parameters; -->
+        <!-- without it, Dirichlet would disappear from the prior dropdown. -->
         <subtemplate id='Dirichlet' class='beast.base.spec.inference.distribution.Dirichlet' mainid='[top]'
+        	suppressInputs='beast.base.spec.inference.distribution.Dirichlet.param'
             hmc='
             Dirichlet/alpha/=ParametricDistributions/Dirichlet/mean/,
             Dirichlet/offset/=ParametricDistributions/Dirichlet/offset/'>
             <![CDATA[
 			<distr spec="beast.base.spec.inference.distribution.Dirichlet">
+                <param spec="beast.base.spec.inference.parameter.SimplexParam" dimension="1" value="1.0" estimate="false"/>
                 <alpha spec="beast.base.spec.inference.parameter.RealVectorParam" domain="PositiveReal" estimate="false">1.0</alpha>
             </distr>
 ]]>