ListGrid: Mouseover / selection appear one or several rows below the mousepointer

[ch.horisberger]

Version:

gwt.version: 2.0.4
smartgwt.version: 2.2

Encountered on OS / Browser (e.g. WinXP, IE6-7, FF3):

WinXP, Firefox 3.6.12

Detailed description (please be as specific as possible):

While hovering the mouse over a ListGrid not the row under the mouse pointer, but a different row further below is highlighted (or selected, on mouseclick).

The further down the mouse pointer is over the ListGrid, the bigger the offset between mousepointer position and the (incorrectly) highlighted row gets. So in the first few rows the correct row under the mousepointer is highlighted. At the bottom of the ListGrid, the distance between mouse pointer position and highlighted row can be as much as 5-6 rows.

The bug appears on seemingly random occasions (only about every few dozend times the application is started). Despite intensive testing of different preconditions (same application state, empty browser cache, re-deploy application, etc.) no way was found to reproduce this bug consistently.

However, it seems to appear mostly when the all the images used for the listgrid layout are beeing loaded the first time while the application is starting up (when browser cache is empty). Therefore some racing-condition concerning the size of loaded/not-yet-loaded images used for the listgrid layout/dimensions is suspected to be the cause.

The bug appears in web-mode as well in development mode.
No error/warning message was displayed in the the development console.
When opening Debug-Console (SC.showConsole()) the bug disappears.
When restarting the application, reloading the page or restarting the browser, the bug disappears.

[ch.horisberger]

I believe that found the cause of the bug:

It only happens if html <img> tags are used within a ListGrid CellFormatter, while not setting the height of the image explicitly.

My assumption is that if the image has not finished loading at the point where the ListGrid layout is calculated, its true size is not available and therefore the calculation of the row heights somehow messes up. This leads to the described bug.

Setting the height of the img explicitly in the <img> tag prevents this.

SmartGWT Bugreport: http://code.google.com/p/smartgwt/issues/detail?id=541

[Isomorphic]

Not a bug - if you embed images in ListGrid cells and expect auto-sizing to occur, then you need to set an explicit size on those images.

[will-gilbert]

gwt.version: 2.1.1 or 2.0.4
smartgwt.version: 2.2 or 2.4

MacOSX, Firefox 3.6.8

We are also experiencing this type of 'mouse pointer/highlighted ListGrid record' slippage with large ListGrid tables, > 200 visible rows.

The further down the ListGrid the further below the mouse pointer is from the highlighted ListGrid record. When the mouse is clicked, selection goes to the highlighted record not the record which the mouse pointer is over. This probably the best behavior all things considered.

We only see this on FireFox and not on the Safari or Chrome browsers.

Our FireFox users cannot select the last record and hence is more of a cosmetic problem and a minor inconvenience.

We have no IMG tags in the any of the records in the ListGrid.

[Isomorphic]

You haven't provided any new information - creating a standalone test case is the way to get the problem resolved (whether it turns out to be usage issue or bug).

[a.reiter]

facing the same problem where ListGrid with >50 entries looks very strange
the current selected entry is not under the mouse cursor... actually exactly the same as described by ch.horisberger, except we do not have any image elements

[weiqj]

I am still experiencing this problem with latest 4.0P.
It occurs occasionally with the same records, no image in any cell.
Sometimes closing the grid and reopen it will make problem disappear.
Really annoying.

[weiqj]

The TreeGrid in the showcase sometimes have this exact problem on Google Chrome as well.

[bsoyluoglu]

I'm also having the same problem not just on ListGrids but also on SelectItems and ComboItems non of which has an <img> tag inside. Does anybody found any work arounds. There are infinite number of forum entries regarding this problem but they all refer to the usage of <img> tag.

[bsoyluoglu]

Standalone testcase

http://www.smartclient.com/smartgwt/showcase/#live_grid

Before opening the link change the browser zoom to 125% once the page is loaded scroll to the very bottom. Change the zoom to 90% and hover over the rows. The problem occurs on many other occasions but I found that this was the easiest to reproduce. It may seem very trival but if the grid loads as mentioned above that posses a problem and it does load as stated.

[ssouthwell]

Listgrid Hovers messed up

I posted a reproducible test case here that may be related: http://forums.smartclient.com/showthread.php?t=28803

I'm not noticing a particular vertical offset with mine though. It's more like a very random issue with SmartClient picking the wrong target for the hover.

[bsoyluoglu]

Standalone testcase downloadable

I posted a reproducible test case here that may be related: http://forums.smartclient.com/showthread.php?t=28803

I'm not noticing a particular vertical offset with mine though. It's more like a very random issue with SmartClient picking the wrong target for the hover.

Thank you for the test case I've changed it a bit to demonstrate that the error can be seen with no modifications. All you need are a simple listgrid, large amounts of data and a browser zoom that is set to 125% (in my case I am using 125% as a default setting) or something other than 100%. You can not assume that all the users will use a 100% zoom level.

Isomorphic should stop giving excuses that it is a usage error, which obviously is not and there are tons of issues about this.

If you change your browser zoom level the showcase also does not work as expected even the treegrid on the left side is messed up.

To clarify, the steps are change the default zoom level to 125% then run the "gridtest.html".

[Isomorphic]

We don't give excuses - but unfortunately there are far too many intractable bugs across different browsers for it it be possible to suppose browser zoom.

We will re-evaluate the situation regarding browser zoom periodically, and we will support it when it is feasible to do so.

In the meantime, we have not seen any test case that reproduces this issue if browser zoom is not enabled. If you disagree, please produce such a test case, and make sure you have tested it with the latest patched SDK (from SmartClient.com/builds).

[bsoyluoglu]

To be honest I can't be positive about the case if the issue will show up when the browser zoom is set to 100%. I couldn't find any concrete proof that it will.

Needless to say so the problem also shows up on SelectItems TreeGrids basically anything that uses a ListGrid.

However thanks for the quick response.