This is since Aurora47.0a2. Reproducible: always Steps To Reproduce: 1. Move browser window to the bottom of screen so that only the toolbar(TitleBar/MenuBar/NavBar) is visible. 2. Open "Clear Recent History" (Ctrl+Shift+Del) Actual Results: "Clear Recent History" dialog pops up out of screen. I.e. it is not visible. Expected Results: "Clear Recent History" dialog should pop up within the screen.

Regression window: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=98756a36223c1a2b51cd0368736b728429038caf&tochange=a9f9b36c1a2eec7626e6b749e46ab0a8bf3323e2 Regressed by: Bug 890156

Is this problem still present in the latest Nightly?

(In reply to Jonathan Kew (:jfkthame) from comment #2) > Is this problem still present in the latest Nightly? Yes, I can still reproduce. https://hg.mozilla.org/mozilla-central/rev/f0c0480732d36153e8839c7f17394d45f679f87d Mozilla/5.0 (Windows NT 6.1; WOW64; rv:48.0) Gecko/20100101 Firefox/48.0 ID:20160314030215

OK, thanks; I'll try to debug. Is this Win7 only (not 8.1 or 10)?

It happens on win10 too. Okay, It happens if detail pane was expanded at once. Then the problem will persist across session. Steps To Reproduce: 1. Open "Clear Recent History" (Ctrl+Shift+Del) 2. Click expand icon to expand details pane 3. Close the dialog 4. Move browser window to the bottom of screen so that only the toolbar(TitleBar/MenuBar/NavBar) is visible. 5. Open "Clear Recent History" (Ctrl+Shift+Del)

This is a lot like bug 1242449; it's the problem of sizing vs positioning. We need to position the window (on the appropriate screen, so that it gets the right resolution) before we can size it properly; but we need it sized properly before we can constrain its position correctly. Bug 1242449 fixed this for windows that are sized based on their XUL-specified dimensions, but we also need to handle the case where the window is intrinsically-sized. Try run with this patch: https://treeherder.mozilla.org/#/jobs?repo=try&revision=266a8b9f5997

https://hg.mozilla.org/integration/mozilla-inbound/rev/21e9dd187ca87f1eec65888aa373559a2c3e9ab1 Bug 1255645 - Ensure nsXULWindow constrains the window to the bounds of its screen after applying intrinsic sizing (if appropriate), by re-doing positioning after the window has been sized properly. r=emk

Comment on attachment 8730731 [details] [diff] [review] Ensure nsXULWindow constrains the window to the bounds of its screen after applying intrinsic sizing (if appropriate), by re-doing positioning after the window has been sized properly Approval Request Comment [Feature/regressing bug #]: 890156 (per-monitor dpi) [User impact if declined]: Dialog windows such as "Clear Recent History" may open largely off-screen, making them difficult to interact with (or even to find, if the user doesn't realize what happened). [Describe test coverage new/current, TreeHerder]: Tested manually. [Risks and why]: Low - minimal patch in XUL window setup to ensure the position is constrained properly. [String/UUID change made/needed]: none Note that although this is a regression caused by the Windows per-monitor dpi changes, it can affect users without per-monitor dpi support (e.g. Win7) as well, and it will persist even if we disable per-monitor dpi support via the firefox.exe manifest. As such, we need this fix on Aurora even if we decide to hold back actually shipping per-monitor dpi to users for another cycle.

Hi, backed this out in https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&revision=7c210149e23c since one of the changes caused reftest failures like : https://treeherder.mozilla.org/logviewer.html#?job_id=23888478&repo=mozilla-inbound

Backout: https://hg.mozilla.org/integration/mozilla-inbound/rev/a7e73c88ae0d

https://hg.mozilla.org/integration/mozilla-inbound/rev/798395b00a7d03203266b6d3d029846255ff7686 Bug 1255645 - Ensure nsXULWindow constrains the window to the bounds of its screen after applying intrinsic sizing (if appropriate), by re-doing positioning after the window has been sized properly. r=emk

(In reply to Carsten Book [:Tomcat] from comment #10) > Hi, > > backed this out in > https://treeherder.mozilla.org/#/jobs?repo=mozilla- > inbound&revision=7c210149e23c since one of the changes caused reftest > failures like : > > https://treeherder.mozilla.org/logviewer.html#?job_id=23888478&repo=mozilla- > inbound That was bug 1255158 (unrelated, but pushed at the same time), so I've re-landed this one.

Comment on attachment 8730731 [details] [diff] [review] Ensure nsXULWindow constrains the window to the bounds of its screen after applying intrinsic sizing (if appropriate), by re-doing positioning after the window has been sized properly Trying to improve multi-mon drag-drop-resize experience, Aurora47+

Note that this won't transplant cleanly to aurora right now; it builds on the patch in bug 1242449 (where an approval request is still pending), so we need that one to be uplifted first.

Reproduced the initial issue using old Nightly from (2016-03-24), verified that the issue is fixed using latest Developer Edition 48.0a2 and Firefox 47 beta 8 on Windows 10, 8.1 and 7.