diff --git a/src/CallBlock.tsx b/src/CallBlock.tsx
index f93dced..b99acbc 100644
--- a/src/CallBlock.tsx
+++ b/src/CallBlock.tsx
@@ -1,6 +1,6 @@
 import { useState } from "react";
 
-import { apply, UnifyError, assignFn, getType } from "dope2";
+import { apply, UnifyError, assignFn, getType, getSymbol, symbolFunction } from "dope2";
 
 import { Editor, type EditorState } from "./Editor";
 import { Value } from "./Value";
@@ -97,7 +97,8 @@ export function CallBlock({ state, setState, onResolve }: CallBlockProps) {
     <FunctionHeader
       fn={state.fn}
       setFn={setFn}
-      onFnResolve={onFnResolve} />
+      onFnResolve={onFnResolve}
+      input={state.input} />
     <div className="functionParams">
       <div className="outputParam">
         {/* Sequence of input parameters */}
@@ -116,7 +117,7 @@ export function CallBlock({ state, setState, onResolve }: CallBlockProps) {
   </span>;
 }
 
-function FunctionHeader({ fn, setFn, onFnResolve }) {
+function FunctionHeader({ fn, setFn, input, onFnResolve }) {
   if (fn.kind === "call") {
     // if the function we're calling is itself the result of a function call,
     // then we are anonymous, and so we don't draw a function name
@@ -129,9 +130,28 @@ function FunctionHeader({ fn, setFn, onFnResolve }) {
     return <FunctionHeader
       fn={fn.fn}
       setFn={fnFn => setFn({...fn, fn: fnFn})}
-      onFnResolve={onFnFnResolve} />;
+      onFnResolve={onFnFnResolve}
+      input={fn.input} />;
   }
   else {
+    const filterCompatibleFns = ([_name, dynamic]: [string, Dynamic]) => {
+      if (input.resolved) {
+        try {
+          const type = getType(dynamic);
+          if (getSymbol(type) !== symbolFunction) {
+            return false;
+          }
+          assignFn(type, getType(input.resolved));
+        } catch (e) {
+          if (!(e instanceof UnifyError)) {
+            throw e;
+          }
+          return false;
+        }  
+      }
+      return true;
+    }
+  
     //  end of recursion - draw function name
     return <div className="functionName">
       &#119891;&#119899;&nbsp;
@@ -141,7 +161,7 @@ function FunctionHeader({ fn, setFn, onFnResolve }) {
         focus={false}
         onResolve={onFnResolve}
         onCancel={() => {/*todo*/}}
-        filter={() => true} />
+        filter={filterCompatibleFns} />
     </div>;
   }
 }
diff --git a/src/Editor.tsx b/src/Editor.tsx
index a2eb6f8..8c3fbf4 100644
--- a/src/Editor.tsx
+++ b/src/Editor.tsx
@@ -75,10 +75,14 @@ export function Editor({state, setState, onResolve, onCancel, filter, focus}: Ed
     e.preventDefault();
     setNeedCommand(false);
     // u -> pass Up
-    if (e.key === "u" || e.key === "Enter" || e.key === "Tab") {
+    if (e.key === "u" || e.key === "Enter" || e.key === "Tab" && !e.shiftKey) {
       onResolve(state);
       return;
     }
+    if (e.key === "Tab" && e.shiftKey) {
+      setNeedCommand(false);
+      focusPrevElement();
+    }
     // c -> Call
     if (e.key === "c") {
       // we become CallBlock
diff --git a/src/InputBlock.css b/src/InputBlock.css
index 2492cbb..e9dd622 100644
--- a/src/InputBlock.css
+++ b/src/InputBlock.css
@@ -26,7 +26,7 @@
   margin-left: 4px;
   border: solid 1px dodgerblue;
   cursor: pointer;
-  max-height: calc(100vh - 44px);
+  max-height: calc(100vh - 64px);
   overflow: auto;
   z-index: 10;
   background-color: white;
diff --git a/src/InputBlock.tsx b/src/InputBlock.tsx
index fea4c4c..c070d3e 100644
--- a/src/InputBlock.tsx
+++ b/src/InputBlock.tsx
@@ -2,7 +2,7 @@ import { Double, getType, Int, newDynamic, trie } from "dope2";
 import { focusNextElement, focusPrevElement, setRightMostCaretPosition } from "./util/dom_trickery";
 import { parseDouble, parseInt } from "./util/parse";
 
-import { useEffect, useRef, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 import { Type } from "./Type";
 
 import "./InputBlock.css";
@@ -29,12 +29,13 @@ const computeSuggestions = (text, env, filter) => {
   const ls = [
     ... (asDouble ? [[asDouble.toString(), newDynamic(asDouble)(Double)]] : []),
     ... (asInt ? [[asInt.toString(), newDynamic(BigInt(asInt))(Int)]] : []),
-    ... trie.suggest(env.name2dyn)(text)(10),
+    ... trie.suggest(env.name2dyn)(text)(Infinity),
   ]
   return [
     ...ls.filter(filter), // ones that match filter come first
     ...ls.filter(s => !filter(s)),
-  ];
+  ]
+  // .slice(0,30);
 }
 
 export function InputBlock({ state, setState, filter, onResolve, onCancel }: InputBlockProps) {
@@ -48,7 +49,7 @@ export function InputBlock({ state, setState, filter, onResolve, onCancel }: Inp
   }
 
   const singleSuggestion = trie.growPrefix(env.name2dyn)(text);
-  const suggestions = computeSuggestions(text, env, filter);
+  const suggestions = useMemo(() => computeSuggestions(text, env, filter), [text]);
 
   useEffect(() => {
     setI(0); // reset
@@ -186,7 +187,7 @@ function Suggestions({ suggestions, onSelect, i, setI }) {
       {suggestions.map(([name, dynamic], j) =>
         <div
           key={`${j}_${name}`}
-          className={i === j ? "selected" : ""}
+          className={(i === j ? " selected" : "")}
           onMouseEnter={onMouseEnter(j)}
           onMouseDown={onMouseDown(j)}>
             {name} :: <Type type={getType(dynamic)} />
diff --git a/src/Type.css b/src/Type.css
index c103aae..d97e4b0 100644
--- a/src/Type.css
+++ b/src/Type.css
@@ -58,7 +58,7 @@
 
 .iteratorType {
   border-style: dashed;
-  animation: flickerAnimation 500ms steps(1) normal infinite;
+  /* animation: flickerAnimation 500ms steps(1) normal infinite; */
 }
 
 /* Animations */