ComboBox causes ScrollableView to scroll down

[Paul Christopher]

Description:

A combo box placed into a scrollable view causes - when opened - the view to scroll down. Moreover the selection list is misplaced. There is quite a huge distance between the text box and the selection list (see screenshot before.png and after.png).

Steps to reproduce:

Use the attached test case. Run it on Firefox7. Click into the text box so as to open the selection list of the combo box. This will cause the whole view to scroll down. The selection list is placed quite in some distance to the text box.

Dojo version: dojo-1.7.rc

Browser: Firefox7

[Paul Christopher]

Added new test case (index2.html, before2.png, after2.png).

• The view even scrolls down if there is no need for scrolling. This makes my iPad app behave quite awkward. Maybe this scrolling behaviour makes sense on low-res devices but not on an high-res devices like the iPad.
• The select box is misplaced in this test case, too.
• Scrolling the view does not close the drop down select box. Is this intended behaviour? Actionsheets are normally closed if the user clicks somewhere else on the screen.
• Having closed the drop down box again, scrolling seems to be broken in some way: you cannot scroll back to the top. You need to scroll down to the very end of the page so as to be able to scroll back to the top again.

This all happens to me with dojo-1.7.rc1 and Firefox 7.0.1.

[ykami]

I confirmed the problem.

Doug, do you know what scrolls the page when ComboBox gets focus?

[Douglas Hays]

possible fix

[Douglas Hays]

Fix needs review/testing

[ykami]

Doug, onoat has reviewed and tested the fix.
Onoat, could you explain the test result and your findings if any?

[Atsushi Ono]

Doug, I have reviewed and tested the fix on iPhone and Android. It works quite better on both devices, and the code looks good to me.

One little concern is that ScrollableView's scrolling becomes choppy while ComboBox dropdown stays open because the dropdown position is adjusted every 50ms. I think it might be better to close ComboBox dropdown when starting to scroll the ScrollableView (on 'touchstart' event?), but I guess this is closely related to #14124. We'll work on #14124 to enable this.

[Douglas Hays]

updated fix with performance fix while scrolling, requires #14124

[Douglas Hays]

Fix needs more test time before being backported to 1.7 along with #14124.

[Douglas Hays]

In [27307]:

Fixes #14096. Reposition ComboBox? popup on a timer to avoid asynchronous transform/position problems. Added a testcase with ComboBox? inside a ScrollableView?.