Code Sample, a copy-pastable example if possible

import numpy as np
import pandas as pd
a = pd.Panel({"A":{"a":[1,2,3,4,5], "b":[10, 20, np.nan, 40, 50]})
a.ffill(axis=0)["A"]
a.ffill(axis=1)["A"]
a.ffill(axis=2)["A"]

Problem description

change to the param axis doesn't change the result. It all gives:

 a     b

0 1.0 10.0 1 2.0 20.0 2 3.0 20.0 3 4.0 40.0 4 5.0 50.0

Expected Output

 a     b

0 1.0 10.0 1 2.0 20.0 2 3.0 3.0 3 4.0 40.0 4 5.0 50.0

Output of pd.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.5.2.final.0 python-bits: 64 OS: Windows OS-release: 7 machine: AMD64 processor: Intel64 Family 6 Model 60 Stepping 3, GenuineIntel byteorder: little LC_ALL: None LANG: None LOCALE: None.None pandas: 0.19.2 nose: 1.3.7 pip: 9.0.1 setuptools: 32.1.3 Cython: 0.25.2 numpy: 1.12.0 scipy: 0.18.1 statsmodels: 0.6.1 xarray: None IPython: 5.1.0 sphinx: 1.4.6 patsy: 0.4.1 dateutil: 2.6.0 pytz: 2016.10 blosc: None bottleneck: 1.1.0 tables: 3.2.2 numexpr: 2.6.1 matplotlib: 1.5.3 openpyxl: 2.3.2 xlrd: 1.0.0 xlwt: 1.1.2 xlsxwriter: 0.9.3 lxml: 3.6.4 bs4: 4.5.1 html5lib: None httplib2: None apiclient: None sqlalchemy: 1.0.13 pymysql: 0.7.9.None psycopg2: None jinja2: 2.8 boto: 2.42.0 pandas_datareader: None

Comment From: jreback

dupe of #8251