diff --git a/de.prob.eventb.disprover.ui/src/de/prob/eventb/disprover/ui/DisproverPreferences.java b/de.prob.eventb.disprover.ui/src/de/prob/eventb/disprover/ui/DisproverPreferences.java
index 6e32ed679ff21cbb8c92d9bfb4625100ba2da458..f2f8e38d7705276fa88e8d607295f8b5e142bc27 100644
--- a/de.prob.eventb.disprover.ui/src/de/prob/eventb/disprover/ui/DisproverPreferences.java
+++ b/de.prob.eventb.disprover.ui/src/de/prob/eventb/disprover/ui/DisproverPreferences.java
@@ -66,6 +66,7 @@ public class DisproverPreferences extends PreferencePage implements
 		timeoutTextField = new Text(pageComponent, SWT.NONE);
 		int timeout = prefNode.getInt("timeout", 1000);
 		timeoutTextField.setText(Integer.toString(timeout));
+		timeoutTextField.setSize(100, timeoutTextField.getSize().y);
 		timeoutTextField.addVerifyListener(new VerifyListener() {
 			@Override
 			public void verifyText(VerifyEvent e) {