Why does dragging an objective-C header or code file from one folder to another make it turn red in Xcode 4.6? -

Why does dragging an objective-C header or code file from one folder to another make it turn red in Xcode 4.6? -

i have xcode 4 objective-c project contains 150 .m , .h files in it. code underlying project not correspond in underlying disk construction folders shown in xcode project. part.

what don't why xcode won't tell me why can create new project groups , move items them, no problems, existing project folders cause project become broken, , code no longer build 1 time move .m files or .h files different group. when broken shows file in red. frustrating , confusing.

in screenshot below, left side of image before shows state before, when good, right side shows reddish (missing) file after moving group. given groups don't represent folder on disk, not expect moving 1 grouping break things. does, , not. particular xcode issue upsets me lot.

in old days of friendly mac user-interfaces, nail ⌘+i , info properties of objects, or right click , properties of via context menu. groups (folder icons) in xcode projects have no properties item in context (right click menu) , yet these groups not alike. what's these identical looking groups?

secondly, how person larn how reorganize both on-disk-folder-organization , visual grouping organization, in way not leave bloodied , beaten? (xcode 4 hard ide version have ever used, this, i'm sure i've missed of import documentation on dealing folders , files , on.)

update: file inspector (identity inspector in utilities menu) key mystery, how new user find (other painful experience) still unknown me. don't understand about, various choices available in path drop-down, , blank or non blank value has no description or help, cryptic icon , either name of real on-disk-folder or else grayness text field saying none:

this sort of thing doesn't happen out of blue. in case, has happened user has opened .xcodeproj , unaware of difference between various relative or absolute path options group can part of. group in xcode shown same manilla color folder-icon within xcode project, no matter modes or properties has defined within of it.

by default simplest case create new folder grouping object in xcode , it's purely cosmetic organizational tool has no disk location info stored in it.

this not thing these groups do, , not "mode" these groups can used in. these groups can used point @ folder , "things in virtual folder somewhere else, either underneath project's main folder in subdirectory, or somewhere else on hard-drive, either stored in relative path, or absolute path format". when used this, these things remind me of windows "shortcut" object on desktop, or mac "alias" object in finder.

dragging file 1 grouping not move different folder on disk. moves reference file name, group, might mean after drag file, haven't moved it, or copied, or relocated in way, you've moved alias place resolve real file, place can't. xcode helpfully turns reddish you, without helpful error message happened.

how prepare it? in case, go identity inspector pane in utilities menu, , either decide clear out bogus value in place have shown in image in original question had "classes". clearing out value invalid not easy because xcode requires find root folder of project , select that, , 'clear" relative or absolute path property on folder-group.

alternatively, can leave folder alone, , don't drag files grouping group b without first checking relative or absolute path reference.

what still seems horrible me xcode tutorials tell "use xcode manage project's contents, don't drag files around in finder within xcode project directory", , that's advice, leads me assume xcode provides total , intuitive physical (and virtual) group-folder organization tools. not. example, imagine inherit project has .m , .h files scattered through 4 physical folders underneath main xcode project folder , want move files around. have combination of tricky things within xcode, , either in terminal or in finder, in order reorganize folder. complications involved in moving items around in version command tool of selection added upon top of that, , xcode's limited back upwards git , subversion, have tricky mess.

objective-c xcode cocoa xcode4.6