How to align elements with GTK library in C/C++

  alignment, c++, gtk


The image show two rows of a gtk table with three column.
The first and the third column contains a label with a description, in particular the first one is the name of a test that is in execution while the third is a description of the running state of the test.
The second column contain a progress bar for each row and as you can see from the image it is not aligned with the two labels, even if they belong to the same row.
How can I fix this problem?

Source: Windows Questions C++