910023 - [e10s] Select dropdowns should be correctly positioned and sized

Status: RESOLVED WORKSFORME

(Core :: XUL, defect)

Description

[:Felipe Gomes (needinfo for replies!)]

In bug 897060 we implemented support for displaying the dropdowns from <select> widgets in the parent, by opening a menupopup in the x/y position in the screen underneath the widget.

It works reasonably well but differs in behavior from the non-e10s <select> popups in various circumstances, such as:
 (1) when there's not enough space until the edge of the screen (right or bottom) to open the popup, it shifts the popup to fully display it, which might cover the original <select> widget in the page (as opposed to flipping the anchor point and displaying it above the widget)

 (2) (multiple monitors untested)

 (3) no attempt is currently made to properly size the popup width. The menupopup code calculates a reasonable default width to fit the content, but <select> dropdowns should have the same size as the main widget. This depends on bug 910022 because to have the same width we need to use the same font/font-size/margins/paddings etc.


For (1) and (2), I'd like to extend openPopup to support anchoring in a Rect as if it's anchored in an element, instead of fiddling with front-end code to make it work.

For (3) I hope that bug 910022 will fully solve it, but there might be necessary to make small adjustments depending on the specific appearance of the menupopup per platform

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

If in bug 910022 we decide to not use <option> styling (except maybe for colors) and go with native styling, then in this bug we should match the width of the <select> to the styling of the dropdown, not the other way around.

We have to be careful here to ensure that the dropdown never pops up over browser chrome (which can be annoying and/or insecure).

Comment 2

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Attachment: testcase.html

I have seen the same problem today for my online banking account. I reduced the content of the web page to this minimized testcase. As you can see the width is not correct, and inside the popup we strangely show list dots on the left side when e10s is enabled.

Comment 3

[Neil Deakin]

All of these are covered by others bugs, so I'm just going to close this one.