Announcement

**Isomorphic** · 4 Jun 2014, 14:36

See FAQ: you should include a JavaScript stack trace with any JavaScript error, this will give us a chance at identifying the cause.

**karankhokhani** · 5 Jun 2014, 08:22

I have attached a part of the stack trace in debug level logging. Please let me know if you need any other info.

Attached Files

overflowStackTrace.txt (32.6 KB, 181 views)

**Isomorphic** · 5 Jun 2014, 08:54

Ah, this isn't actually a JavaScript error, just a warning being logged.

This is a rare condition we don't know how to re-create - the last time we saw it was Mozilla 1.2. It should be a harmless warning, but if you find a way to reproduce it that you can isolate to a test case, let us know and we can look into whether it could have any side-effects.

**karankhokhani** · 5 Jun 2014, 09:04

I am trying to isolate it to a test case but no luck yet.

In my case, I am setting the overflow to a HTMLPane. Due to the error/warning, the HTMLPane keeps loading again and again infinitely. This is a major issue in my application. I am trying to write a standalone test case which can reproduce this issue but if I don't succeed, do I need to downgrade back to 3.1?

**Isomorphic** · 5 Jun 2014, 09:21

We're not sure why you assume the warning is related to the reloading issue - it doesn't seem connected from what we can see.

An issue that occurs on an upgrade could be a bug (which we can fix if you can make it reproducible for us) or could be a longstanding usage issue that is revealed by a new version of the framework.

So keep trying for a test case.

**karankhokhani** · 5 Jun 2014, 09:33

If I don't set the overflow to visible or if I change it to auto, I don't get that warning any more and htmlpane does not keep reloading.

The HTMLPane has a Frame added as its child. When the Frame is set to scrolling, the HTMLPane needs to be set to overflow visible and when the Frame is set to not scrolling, the HTMLPane overflow should be set to auto. That is why I need to set the overflow to visible for the pane.

**Isomorphic** · 5 Jun 2014, 09:39

To clarify, setting overflow:visible will not cause an HTMLPane to auto-size to content loaded *in a frame*, although in some browsers and some modes, it might have looked like some kind of auto-sizing was going on, because browsers can also have issues with clipping content correctly in iframes. This is the kind of possible longstanding usage issue we were referring to.

As far as getting past your issue without isolating to a test case / possible bug, if setOverflow() isn't working, creating a new HTMLPane each time should work.

**karankhokhani** · 5 Jun 2014, 11:52

Here is the standalone test case which reproduces the issue. Setting overflow on the html pane causes its child frame to reload again and again. I tested the same code in 3.1 (IE, FF and chrome) and the issue did not happen there.

Code:

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.dom.client.FrameElement;
import com.google.gwt.event.dom.client.LoadEvent;
import com.google.gwt.event.dom.client.LoadHandler;
import com.google.gwt.user.client.ui.NamedFrame;
import com.smartgwt.client.types.Overflow;
import com.smartgwt.client.widgets.HTMLPane;
import com.smartgwt.client.widgets.Label;
import com.smartgwt.client.widgets.layout.VLayout;

public class OverflowTest implements EntryPoint {

    private int loadCount = 0;
    private Label countLabel;
    private HTMLPane pane;
    private NamedFrame frame;

    public void onModuleLoad() {

        VLayout wrapper = new VLayout();
        wrapper.setPadding(10);
        wrapper.setMembersMargin(10);
        wrapper.setBorder("2px solid green");

        pane = new HTMLPane();
        pane.setHeight(500);
        pane.setWidth(500);
        pane.setOverflow(Overflow.AUTO);
        pane.setBorder("2px solid red");

        frame = new NamedFrame("frame");
        frame.setUrl("http://www.smartclient.com/");
        frame.setWidth("100%");
        frame.setHeight("100%");
        frame.addLoadHandler(new LoadHandler()
        {
            
            @Override
            public void onLoad(LoadEvent event)
            {
                loadCount++;
                countLabel.setContents("Loaded " + loadCount + " times.");
                setOverflowVisible();
                setOverflowAuto();                
            }
        });

        countLabel = new Label("Loaded " + loadCount + " times.");
        countLabel.setWrap(false);

        wrapper.addMember(countLabel);       
        pane.addChild(frame);
        wrapper.addMember(pane);     

        wrapper.draw();
    }

    private void setOverflowVisible()
    {
        /*FrameElement frameElement = frame.getElement().cast();        
        frameElement.setScrolling("auto");

        pane.redraw();
        pane.adjustForContent(true);*/
        pane.setOverflow(Overflow.VISIBLE);
    }

    private void setOverflowAuto()
    {
        /*FrameElement frameElement = frame.getElement().cast();       
        frameElement.setScrolling("no");
        frameElement.setFrameBorder(0);
        frameElement.setAttribute("border", "0");*/

        pane.setOverflow(Overflow.AUTO);
    }
}

Hope this helps.

Thanks

**Isomorphic** · 5 Jun 2014, 13:44

The problem is that setOverflow() needs to remove the iframe from the DOM and re-add it - this causes the browser to re-load the content (with no known workaround - see this). Since this fires the load event again, your code goes into an infinite reload loop.

The best solution is the one we previously proposed - create a new HTMLFlow each time.

**karankhokhani** · 5 Jun 2014, 15:57

Creating a new HTMLPane each time won't work for me. Any reason why setOverflow did not reload the frame in 3.1 and reloading in 4.1?

**Isomorphic** · 5 Jun 2014, 16:00

4.x now has to remove the content from the DOM to switch overflow modes, in some browsers and for some mode changes. This is because we were able to reduce the necessary number of DOM elements for most controls in 4.x, but due to a variety of browser bugs, different overflow modes like "visible" require more/different elements than other modes like "auto".

There doesn't really seem to be a way that creating an HTMLPane each time could not work - there are so few properties that apply to this class, it's trivial to re-create instead of re-use.

**karankhokhani** · 5 Jun 2014, 16:12

We extend that class and have our own sub calss. There are a lot of other variables and listeners associated with the sub class. Re-creating it each time won't work for us.

**Isomorphic** · 5 Jun 2014, 16:14

OK, then the simplest solution is to avoid going into an infinite loop when the iframe reloads - as we mentioned that's happening in your test case because you're toggling the overflow setting back and force every time content loads.

**karankhokhani** · 5 Jun 2014, 16:21

The test case was written purposely like that to recreate the issue.

I will take a look at my code to see if I can avoid that situation from occurring. Thank you for looking into it.

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setting overflow visible is throwing parentNode null error

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