problem with x-axis labels after overlapping 2 box plots

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I have the following code to compare two sets of box plots and there seems to be two misaligned x-axis labels after doing that! I have no idea what is causing this strange misalignment. Could the use of 'hold' be a problem in this case? Im using matlab 2014. Thanks.
x = rand(5,1);
y = rand(10,1);
z = rand(15,1);
Xpos = [2 5 12];
group = [repmat(Xpos(1), 5, 1); repmat(Xpos(2), 10, 1); repmat(Xpos(3), 15, 1)];
data=[x;y;z];
figure
boxplot(data, group,'positions', Xpos,'colors','k')
hold on
x =2+ rand(5,1);
y = 2+rand(10,1);
z = 2+rand(15,1);
group = [repmat(Xpos(1), 5, 1); repmat(Xpos(2), 10, 1); repmat(Xpos(3), 15, 1)];
data=[x;y;z];
boxplot(data, group,'positions', Xpos,'colors','r')
ylim([0 4])
  4 Comments
Star Strider
Star Strider on 30 May 2014
I can’t reproduce it in R2014a. Looks fine — no duplicated or repeated x values.
To wit:
Although it doesn’t match Dawn’s plot. There may be something strange in Dawn’s workspace (workspace variables?) or in her code that we are not privy to.
The real Question is what Dawn did to get MATLAB mad at her?
Dawn
Dawn on 2 Jun 2014
Edited: Dawn on 2 Jun 2014
On first sight it may look fine but if I try to resize the plot by manually expanding it, the misalignment problem will show up. It happens all the time, even after clearing the workspace and pasting just the exact code that I posted above.
Would appreciate if the kind souls out there could let me know if to same thing happens to you after you resize your plots.

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Accepted Answer

Kelly Kearney
Kelly Kearney on 2 Jun 2014
Edited: Kelly Kearney on 2 Jun 2014
The answer to the "why" is that boxplot, for reasons I've never been able to figure out, doesn't just change the tick positions and labels. Instead, it removes the xticks completely (or y-ticks, in the case of a horizontally-oriented boxplot) and replaces them with text annotation objects. And annotation objects are positioned relative to the figure, not the axis. Apparently slightly differently each time (possibly due to the fact that boxplot also, for reasons unknown, resizes axis, hence changing the figure-to-axis ratios between calls).
The easiest fix:
delete(findall(gcf, 'type', 'text'));
set(gca, 'xticklabelmode', 'auto', 'xtickmode', 'auto');
  3 Comments
dpb
dpb on 2 Jun 2014
...boxplot, for reasons [unknown], doesn't just change the tick positions and labels. Instead, it removes the xticks ... and replaces them with text annotation objects
And how bizzaro!!! :( Seems worthy of bug report fer shure...at least an enhancement request to rid it of such foolishness. Who would ever think of doing such a thing????
Kelly Kearney
Kelly Kearney on 2 Jun 2014
I think the original intent was to allow vertically-rotated tick labels (which is the default with the 'compact' option), but it's a pretty clunky implementation in my opinion.
I use boxplots quite a lot, and got really fed up with the heavy-handed axis changes, to the point that I wrote my own replacement:
Though my version handles multiple datasets a bit differently, and doesn't accept the Group input option.

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