Modified the application for adding the select all in the resource selection, tested the modified application, as per testing, the applied changes did not take effect, check other ways/functions to use for multi-select dropdown, found multi-select JS and CSS, modified the application to apply this on the resource selection, tested the modified application, as per checking, the changes still not take effect, check if there are error encountered in console, as per checking, there is, the multi-select function cannot be found, downloaded the JS and CSS for multi-select for fixing the error, modified the blade and included the CSS and JS downloaded in it, tested the application again, as per testing, the error is now OK and the selection is viewing but the selection output is not OK, the alignment of text into the textbox is misaligned, modified the blade again for fixing, many changes have made but it is not taking effect, proceed in modifying the business unit first, but found out that I can display and be selected the resource selection value per group, it has select all and select all by group, modified the blade again for applying this and modified the extraction of resource query for adding the groupings of business unit per resource, this will be used in the grouping in multi-select dropdown, continued to modify the web application for fixing the dropdown selection values and alignment, an error is encountered when added the business unit in the selection, checked and modified the web application to fixed the error. The fixing is now OK, now modifying the application for fixing the alignment and output.