In MQTT Publisher, the "Client ID" field is not able to retain or save any values. I enter a value in the Client ID field and if i click on any other component in the test plan and come back to the MQTT sampler, the value in the field disappears. Similarly, the "Random Suffix" check box is checked whenever the script is opened, whereas i want the checkbox to be unchecked always.

I am having the same issue too

@tuanhiep - Please do have a look at this issue. I have just downloaded the latest master branch code and the issue still persist.

I have the same issue too.

I believe this is a bug in the code. Here is how I was able to fix it.

1. Modify the MQTTPublisherGui.java file as below.
2. Build and generate a new mqtt-jmeter.jar and place them in your JMETER/lib/ext folder.
3. Reopen JMeter tool.

public void configure(TestElement el) {
....
mqttUser.setEnabled(useAuth.isSelected());
mqttPwd.setEnabled(useAuth.isSelected());

    //Adding the missing "Set" for the following UI elements.
    clientId.setText(sampler.getCLIENT_ID());
    suffixClientId.setSelected(sampler.useRandomSuffix());
    this.connectionPerTopic.setSelected(sampler.isOneConnectionPerTopic());

......

}