使用双重差分时，用coefplot画图，这种截断的图是怎么画出来：
我的代码：
xi:xtreg number before4 before3 before2 current after1 after2 after3 after4 after5 after6 after7 after8 after9 after10 i.appyear*i.ipc3,fe cluster(id)

est store result1

coefplot result1, keep(before4 before3 before2 current after1 after2 after3 after4 after5 after6 after7 after8 after9 after10)  vertical recast(connect) yline(0) xline(4,lp(dash)) coeflabels(before4=2002 before3=2003 before2=2004 before1=2005 current=2006 after1=2007 after2=2008 after3=2009 after4=2010 after5=2011 after6=2012 after7=2013 after8=2014 after9=2015 after10=2016) ytitle("Coefficients") xtitle("Year")

试了差分的时候加入before1 但还是没有截断
我的图