The problem was reported [here](https://sft.its.cern.ch/jira/browse/ROOT-8476).

More work was needed to:
- Create the index.md file
- Make the source files are Doxygen Compliant (formatting, Math formulae)
- Spell check

Move the TUnfold files from hist/hist hist/unfold. Stefan Schmitt did the basic move and fixed some warnings.
More work was needed to:
- Create the CMakeLists.txt files (and Module.mk)
- Create the index.md files
- Modify and create the Linkdef.h files
- Make the source file Doxygen Compliant (formatting, Math formulae)
- Spell check

Add a protection when trying to set text to a non-existant part of the status bar. This fixes Jira #ROOT-8474 Setting status bar of TRootBrowser to 1 column produces error message if a TCanvas is also open.

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

  option `ARR`. as requested here: https://root.cern.ch/phpBB3/viewtopic.php?f=3&t=22732

I encountered the following error and the above change fixed it

Nov 22 22:37:47 thesis jupyter[2811]: [I 22:37:47.646 NotebookApp] The Jupyter Notebook is running at: http://0.0.0.0:8888/
Nov 22 22:37:47 thesis jupyter[2811]: [I 22:37:47.646 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
Nov 22 22:38:20 thesis jupyter[2811]: [I 22:38:20.303 NotebookApp] Kernel started: e416bf37-4f24-4aee-8e25-45c6fbbb85e6
Nov 22 22:38:21 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | Bad config encountered during initialization:
Nov 22 22:38:21 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | The 'std' trait of a ClingKernel instance must be any of ['c++11', 'c++14', 'c++17'], but a value of 'c++1z' <class 'str'> was specified.
Nov 22 22:38:23 thesis jupyter[2811]: [I 22:38:23.308 NotebookApp] KernelRestarter: restarting kernel (1/5)
Nov 22 22:38:24 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | Bad config encountered during initialization:
Nov 22 22:38:24 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | The 'std' trait of a ClingKernel instance must be any of ['c++11', 'c++14', 'c++17'], but a value of 'c++1z' <class 'str'> was specified.
Nov 22 22:38:26 thesis jupyter[2811]: [I 22:38:26.326 NotebookApp] KernelRestarter: restarting kernel (2/5)
Nov 22 22:38:27 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | Bad config encountered during initialization:
Nov 22 22:38:27 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | The 'std' trait of a ClingKernel instance must be any of ['c++11', 'c++14', 'c++17'], but a value of 'c++1z' <class 'str'> was specified.
Nov 22 22:38:29 thesis jupyter[2811]: [I 22:38:29.332 NotebookApp] KernelRestarter: restarting kernel (3/5)
Nov 22 22:38:30 thesis jupyter[2811]: [W 22:38:30.348 NotebookApp] Timeout waiting for kernel_info reply from e416bf37-4f24-4aee-8e25-45c6fbbb85e6
Nov 22 22:38:30 thesis jupyter[2811]: [I 22:38:30.365 NotebookApp] New terminal with specified name: 1
Nov 22 22:38:30 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | Bad config encountered during initialization:
Nov 22 22:38:30 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | The 'std' trait of a ClingKernel instance must be any of ['c++11', 'c++14', 'c++17'], but a value of 'c++1z' <class 'str'> was specified.
Nov 22 22:38:32 thesis jupyter[2811]: [I 22:38:32.338 NotebookApp] KernelRestarter: restarting kernel (4/5)
Nov 22 22:38:32 thesis jupyter[2811]: WARNING:root:kernel e416bf37-4f24-4aee-8e25-45c6fbbb85e6 restarted
Nov 22 22:38:32 thesis jupyter[2811]: [W 22:38:32.664 NotebookApp] Session not found: session_id='19509685-b888-480b-897b-be2cc8fed1cc'
Nov 22 22:38:32 thesis jupyter[2811]: [W 22:38:32.665 NotebookApp] 404 DELETE /api/sessions/19509685-b888-480b-897b-be2cc8fed1cc (192.168.0.24) 3.67ms referer=http://192.168.0.31:8888/notebooks/Untitled.ipynb?kernel_name=cling-c++17
Nov 22 22:38:33 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | Bad config encountered during initialization:
Nov 22 22:38:33 thesis jupyter[2811]: [ClingKernelApp] CRITICAL | The 'std' trait of a ClingKernel instance must be any of ['c++11', 'c++14', 'c++17'], but a value of 'c++1z' <class 'str'> was specified.
Nov 22 22:38:35 thesis jupyter[2811]: [W 22:38:35.349 NotebookApp] KernelRestarter: restart failed
Nov 22 22:38:35 thesis jupyter[2811]: [W 22:38:35.350 NotebookApp] Kernel e416bf37-4f24-4aee-8e25-45c6fbbb85e6 died, removing from map.
Nov 22 22:38:35 thesis jupyter[2811]: ERROR:root:kernel e416bf37-4f24-4aee-8e25-45c6fbbb85e6 restarted failed!
Nov 22 22:38:35 thesis jupyter[2811]: ERROR:root:kernel e416bf37-4f24-4aee-8e25-45c6fbbb85e6 restarted failed!
Nov 22 22:38:35 thesis jupyter[2811]: [W 22:38:35.368 NotebookApp] Kernel deleted before session
Nov 22 22:38:35 thesis jupyter[2811]: [W 22:38:35.369 NotebookApp] 410 DELETE /api/sessions/ff344691-8fd6-4207-902e-01c944bdf7ae (192.168.0.24) 2.13ms referer=http://192.168.0.31:8888/notebooks/Untitled.ipynb

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Remove residual symlink creation (after optimization introduced in 0a976f4a).
For PROOF-Lite, make sure that all the relevant files (including .pcm) are present in the cache.

This allows to interactively adjust histogram parameters before
performing a projection to a lower dimensional representation.

This patch implements ROOT-4515.

Use the tree number, not the pointer; return early if end-of-chain; simplify condition for setting proxies.

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>