Firefox: flickering scrollbars in showcase

[Crack]

1. Go to showcase:
1.1. 12p - https://www.smartclient.com/smartcli...crease=4&dhc=1 (Graphite skin, Medium density)
1.1. 11.1p - https://www.smartclient.com/smartcli...crease=4&dhc=1 (Graphite skin, Medium density)
2. Set "# of Samples" to 1
3. Result area gets blinking scrollbars, like SC couldn't decide whether they are required or not, and keeps adding/removing them in a loop.

Tested on two systems:
* Windows 10, 125% scaling on 1080p screen, 100% scaling in Firefox 60b10
* Windows 10, 100% scaling on 1080p screen, 110% scaling in Firefox 59

Edit: just got the same effect in https://www.smartclient.com/smartcli...tem/reference/ , on all pages that require scrollbars.

[Isomorphic]

There are some native browser limitations related to zoom covers in the javadocs under Browser Zoom. Unfortunately in Firefox, if the user changes the zoom, they need to reload (due to native browser bugs in Firefox).

We didn't download the beta version of Firefox, but we were unable to reproduce a flashing scrollbars problem in your specified scenario, if the page is reloaded as required.

[Crack]

I didn't use zoom in Firefox (it's at "100%"). All I did was:
* change scaling to 125% in Windows 10 - Display settings > Scale and layout (https://www.tenforums.com/tutorials/...html#option1); screen resolution is set at 1920x1080
* go to https://www.smartclient.com/smartcli...crease=4&dhc=1
* change #samples to <= 10 (two rows or less)
Browser: 59.0.2

I just reproduced it on 3rd computer, so I believe you didn't set scaling in Windows, and thought I was writing about changing zoom in Firefox.

[Isomorphic]

We see the issue with OS zoom on Windows 10 and are looking into it.

[markok]

To add additional information to this issue, we have encountered this too today.

For us, it occurs on IE11 with Windows 10 and the effect is a constant flickering of scroll bars in TreeGrid related components. The machine goes to 100% CPU loop redrawing the UI and makes the application basically unusable when this happens. It seems the be somehow related to the Windows 10 OS scaling as it does not occur on Windows 7 and goes away by fiddling the scaling percentage in Display Settings. We were unable to identify any sensible pattern on how the percentage should be set, but it is most likely related to the combination of the resolution of the monitor and the desktop.

We've tried this with the latest SmartGWT LGPL 6.1p nightly build (2018-04-23) and the problem persists.

[Isomorphic]

We looked but do not see this same issue with IE11. If your issue doesn't happen in the cases mentioned in the top post, it's likely different, and you should start a different thread. Please supply specific repro instructions.

[markok]

Ok, sorry for poisoning this thread. We think we've mitigated the issue simply by calling setLeaveScrollbarGap(true) on the components but we are still investigating the issue. We'll open a new thread on the correct forum if we think it is needed.

[Isomorphic]

The oscillation appears to be due to a Firefox bug in which excessive scrollHeight is reported to our Framework in certain situations when zoom is active. We've applied a workaround to address the scrollbar oscillation observed in this specific situation involving Windows 10 OS-level zoom. Currently, the workaround only runs for Firefox since that's the only browser for which we've been ab le to reproduce a problem.

Note that as per our documentation, if you change browser-level zoom, you still need to reload the page to avoid any issues like this, including if you use it in combination with OS-level zoom. Our fix targets only the problem that oscillation persisted with OS-level zoom even with a freshly loaded page.

The fix made it into today's builds of SC 12.0p and newer, and will be in tomorrow's nightly build of SC 11.1p, dated 04-27-2018.

[Crack]

Thanks. I'm aware that changing zoom when page is unsupported and requires page reload.

I confirm that it's fixed in 12.0p, but still bugged in 11.1p. Looks like the fix depends on isc.Browser.winVersion being set to 10, but it's undefined in 11.1.

BTW, seems like you left a runaway debugging line in SC11.1 2018-05-02 build (modules-debug/ISC_Forms.js - this.logWarn("setCanvasSize:" + resizeWidth);)

[Isomorphic]

We'll resolve the Windows 10 check issue for tomorrow's build. The other issue is unrelated, but will be resolved as well.

[Crack]

Thanks, scrollbars behave correctly now.