jQuery Grid Plugin - jqGrid

I use the latest version of jqGrid (4.5.2). If defining a grid where all columns have a specific width, the grid is shown correct in Firefox, but in Chromium the last column is 5*(Amount of columns - 1) to small. I think that this is related to padding (2*2) and border (1) of each column, which seems not to be respected in calculation of the complete width.