Works for me.

Maybe try a newer build? http://dev-builds.libreoffice.org/daily/master/?C=M;O=A

Win 7 Pro 64-bit Version: 5.1.0.0.alpha1+
Build ID: b216cc1b8096eb60c27f67e8c27b7cd756c75e38
TinderBox: Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-11-12_00:06:20
Locale: fi-FI (fi_FI)

Set to NEEDINFO.
Change back to UNCONFIRMED, if the problem persists. Change to RESOLVED WORKSFORME, if the problem went away.

I can not confirm with Version: 5.1.0.0.alpha1+
Build ID: 7272e8df62a12d6172b297d7a82a0265cd1bc44a
TinderBox: Linux-rpm_deb-x86_64@70-TDF, Branch:master, Time: 2015-11-14_23:41:14

Created attachment 120612 [details]
Image-clip with KeyID on recent biuid (18-Nov-2015 01:11)

Created attachment 120613 [details]
Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-11-17_22:33:0

I tried recent build.

Version: 5.1.0.0.alpha1+
Build ID: 510f463099272cec7f2193f3ffa1dbbd20d9f718-GL
TinderBox: Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-11-17_22:33:07

Also,Legend list dose not match the display.

I added some new attachment.

Please, how to reproduce? I've created new chart and legend position correspond with sidebar.

I reproduced error.
It was very simple.

1.Opened at  LireOfficDev.
2.Opend new Calc Sheet by Main Menu.
3.Put some Number "1 2 3 4 5" at the Sheet. 
4.Range select "1 2 3 4 5".
5.Clicked at  "Insert" - "Chart"
6.Made a Chart.
7.Clicked a Legend.
8.Opened Sidebar.

It was very simple.

Created attachment 120620 [details]
"Legend Left" --- Placement:"Top" on Sidebar.

Sounds like this may have been caused by my reorganizing the legend position list in the below commit, but we would need to track down how this scenario shows up.

http://cgit.freedesktop.org/libreoffice/core/commit/?id=66f1e65fde85168ae582ea75f72ebb290caa0a08

I tried with a japanese locale, but no luck.

Version: 5.1.0.0.alpha1+
Build ID: 32d4c03cba399ada807b8ec113a3928aa9e3ff7b
TinderBox: Linux-rpm_deb-x86_64@70-TDF, Branch:master, Time: 2015-11-17_00:57:30
Locale: ja-JP (en_US.UTF-8)

@Junichi: Couldnt reproduce with your steps in comment 7. Please attach a document we can test against.

@Matthew: Any luck reproducing this on your japanese install?

Junichi: does it work ok if you do it in the normal, old dialog?

Created attachment 120639 [details]
Calc_Legend_test_junichi

I atached a ODS file that made my operation.

(In reply to Junichi Matsukawa from comment #11)
> Created attachment 120639 [details]
> Calc_Legend_test_junichi
> 
> I atached a ODS file that made my operation.

The placement of the legend was "Right". I switched it to "Bottom" and it worked ok.

But what if you right-click it - Format legend - Position..?

Win 7 Pro 64-bit Version: 5.1.0.0.alpha1+
Build ID: b216cc1b8096eb60c27f67e8c27b7cd756c75e38
TinderBox: Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-11-12_00:06:20
Locale: fi-FI (fi_FI)

Created attachment 120652 [details]
I changed Sidebar LegendPlacement:"Left"  - Displayed "Top"

I tested again.

1. I changed Sidebar Legend Placement: "Left".
2. Displayed Legend as "Top" on the chart.
3. I clicked 'Format' - 'Legend' on toolbar menue.  The Legend was "Left" on context menu.

reproduce with Japanese/KeyID UI newest master/Windows 7 Pro.
no reproduce en-US UI.

Version: 5.1.0.0.alpha1+ (x64)
Build ID: 32d4c03cba399ada807b8ec113a3928aa9e3ff7b
TinderBox: Win-x86_64@62-TDF, Branch:MASTER, Time: 2015-11-16_23:41:46
Locale: ja-JP (ja_JP)

NEW per comment 14

This sounds like is just an non-updated KeyID or translation issue. @Sophie: Any insight?

Created attachment 120894 [details]
Not operated from the Sidebar

Noｔ reproduced on LibreOffice5.1.0.0.beta1-buildfix1
Build ID: 13010a13177025f633c9b85adcb3edf6920e44e3
Threads 4; Ver: Windows 6.1; Render: GL; 
Locale: ja-JP (ja_JP)


However, it could not be operated from the Sidebar.

Cannot reproduce 5.1.0.1(x86)/Windows Vista.

(In reply to Junichi Matsukawa from comment #18)
Matsukawaさん、再現しなくなっているとのことですし、私の手元でも再現しません。
なので、WFMで閉じさせていただきます。
ご自身で閉じられたほうが、賢明かと存じます。

Hi buffclan.

JP：
フォローありがとうございました。
WFMで閉じるというのはどのようにしたらよいのでしょうか。
ステータスの変更のことでしょうか。