Discovered in LPP-4175:

I've managed to narrow this one down. It's a problem with calling LzFocus.setFocus() on something outside the viewable canvas area in DHTML. Try running the following test case in DHTML:

<canvas width="400" height="600">

    <view width="${canvas.hat.expanded ? 265 : 390}" x="5" height="550"
        y="5" bgcolor="0x00FF00">
        <button width="10" height="10" x="30" y="30">
            <handler name="onclick">
                canvas.hat.setAttribute('expanded', !canvas.hat.expanded);
            </handler>
        </button>
    </view>
    
    <view name="hat" width="120" x="400" height="550" y="5" bgcolor="0xFF00FF">
        <attribute name="expanded" type="boolean" value="false"/>
        <handler name="onexpanded">
            if(this.expanded == true){
                this.slideit.doStart();
            } else {
                this.slideback.doStart();
            }
            LzFocus.setFocus(this.focustext);
        </handler>
        
        <edittext name="focustext" width="${parent.width - 20}" x="10" text="Focus on me."/>
        
        <animator name="slideit" attribute="x" from="400" to="280" duration="5000" start="false"/>
        <animator name="slideback" attribute="x" from="280" to="400" duration="5000" start="false"/>
    </view>

</canvas>

Clicking the button will, for some reason, shift the visible canvas area over to whatever is being focused on off-canvas. The culprit in this case (the Calendar) was:

LzFocus.setFocus(summary.content.title);

Commenting this line out resulted in no weird shifting in the app. Weird...