Fixed a couple of warnings

NSTableView+MoreSizing.m

@@ -1,4 +1,5 @@
 #import "NSTableView+MoreSizing.h"
+#import "NSWindow+Screening.h"
 
 NSString* const constKeyMinWidthAnyColumn = @"minWidthAnyColumn" ;
 NSString* const constKeyMinWidthFirstColumn = @"minWidthFirstColumn" ;
@@ -249,9 +250,10 @@ - (void)proportionWidths:(CGFloat[])defaultWidths {
 }
 
 - (NSTableColumn*)tableColumnOfCurrentMouseLocationWithInset:(CGFloat)inset {
-	NSPoint point = [[self window] convertScreenToBase:[NSEvent mouseLocation]] ;
-	CGFloat mouseX = [self convertPoint:point
-									fromView:nil].x ;
+    NSPoint screenPoint = [NSEvent mouseLocation] ;
+    NSPoint windowPoint = [[self window] pointFromScreenPoint:screenPoint] ;
+	CGFloat mouseX = [self convertPoint:windowPoint
+                               fromView:nil].x ;
 
 	CGFloat spacing = [self intercellSpacing].width ;
 

NSWindow+Screening.h

@@ -0,0 +1,11 @@
+#import <Cocoa/Cocoa.h>
+
+/*
+ @brief    Replacement for deprecated -convertScreenToBase:
+ @details  Why does Apple deprecate stuff you need without providing a
+ replacement?  I do agree that -convertScreenToBase: was poorly named! */
+@interface NSWindow (Screening)
+
+- (NSPoint)pointFromScreenPoint:(NSPoint)screenPoint ;
+
+@end

NSWindow+Screening.m

@@ -0,0 +1,13 @@
+#import "NSWindow+Screening.h"
+
+@implementation NSWindow (Screening)
+
+- (NSPoint)pointFromScreenPoint:(NSPoint)screenPoint {
+    NSRect screenRect ;
+    screenRect.origin = screenPoint ;
+    NSRect pointRect = [self convertRectFromScreen:screenRect] ;
+    NSPoint windowPoint = pointRect.origin ;
+    return windowPoint ;
+}
+
+@end