pgAdmin III commit: Current behaviour of the ExplainPopup, requires a m

Current behaviour of the ExplainPopup, requires a mouse click on the ExplainShape to show it.
A lot of user will not able to figure out that until they accidentally click on that shape or
read the documents carefully.

Also - current implementation does not allow to use the ExplainCanvas in a modal dialog.
For some experiment, I tried to use the ExplainCanvas in a modal dialog and clicked on a shape.

A lot of time on linux, this scenario resulted in a crash or unstable pgadmin application.

The attached patch enables the ExplainPopup to behave like the tooltip for those shapes.
As per my conversation with Dave, I have extended the ExplainPopup using wxTransientPopup or, wxFrame
(where not available wxPopWindow i.e. Mac), just like the wxTipWindow, and also worked on the border
around the ExplainText.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin3.git;a=commitdiff;h=659c13f32483a64bdbde241eb0db56696e29f800
Author: Ashesh Vashi <ashesh.vashi@enterprisedb.com>

Modified Files
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pgadmin/ctl/explainCanvas.cpp       |  305 ++++++++++++++++++++++++++++++-----
pgadmin/include/ctl/explainCanvas.h |   47 +++++-
2 files changed, 307 insertions(+), 45 deletions(-)